Teachers have to confront various problems in practice. Solving these problems is very important because they are related to teacher outcomes, professional develo- pment, and teacher well-being. Research on TPS (teacher?s problem solving) is under the infl uence of MPS (mathematical problem solving), CPS (cognitive problem solving) and SPS (social problem solving). Earlier researches have investigated the problems encountered by teachers. Bnd it remains unknown how teachers defi ne a situation as a problem, select a problem as their target, and attach meaning to their problem solving. Earlier researches borrowed the idea that problem solving was a higher order thinking skill and focused on the assessment and training of teacher?s problem-solving skills. Teacher?s problem-solving skills were often found to be low. But teachers were unable to report the actual skills they used in the process of solving diff erent kinds of problems. Some researchers believe that the lack of support for teachers is another reason that makes teacher?s problem solving diffi cult. Diff erent approaches have been developed to support teacher?s problem solving. But all of these approaches have limitations and teacher?s initiative, needs, and choices in support seeking are often ignored. And it remains unknown how teachers seek support for their problem solving. In this research, the pragmatic paradigm and mixed research methods were adopted to answer these questions. A descriptive and bottom-up approach was used by taking a teacher perspective and a holistic view and stressing the individual and situational diff erences between particular problems. Maximum variation samples were selected from three sample schools and one-month-long chat log entries were selected from a teacher?s chat group. Data collected by narrative interview, semi-structured interview and chat log analysis were combined and compared for narrative, thematic, text and descriptive analysis. Th e results revealed that the participants were facing a variety of problems which could be categorized by their primary problem-solving goal. And learning problems were assumed to be most important to them. Th e participants distinguished problems from quasi problems after a three-step process of problem defi nition. Th ey used 13 diff erent kindsof strategies separately or combined for problem solving. Th e fi ve-step process could take place with or without careful planning. Reviewing the success and failure of the participant?s problem-solving attempts, 22 implications were found for teacher?s problem solving. Th ere were many factors aff ecting participant?s strategy selection and use. Th e factors could cause diffi culties for teacher?s problem solving. And the participants had established an ICT-assisted support system to deal with the diffi culties. Th e support system consisted of problems, goals, diffi culties, needs, channels and supports. Based on the analysis of participant?s support seeking, fi ve principles were suggested for building such a system. And there were 16 style indicators that could describe the diff erences between teacher?s problem defi nition, problem solving and support seeking.Teachers have to confront various problems in practice. Solving these problems is very important because they are related to teacher outcomes, professional develo- pment, and teacher well-being. Research on TPS (teacher?s problem solving) is under the infl uence of MPS (mathematical problem solving), CPS (cognitive problem solving) and SPS (social problem solving). Earlier researches have investigated the problems encountered by teachers. Bnd it remains unknown how teachers defi ne a situation as a problem, select a problem as their target, and attach meaning to their problem solving. Earlier researches borrowed the idea that problem solving was a higher order thinking skill and focused on the assessment and training of teacher?s problem-solving skills. Teacher?s problem-solving skills were often found to be low. But teachers were unable to report the actual skills they used in the process of solving diff erent kinds of problems. Some researchers believe that the lack of support for teachers is another reason that makes teacher?s problem solving diffi cult. Diff erent approaches have been developed to support teacher?s problem solving. But all of these approaches have limitations and teacher?s initiative, needs, and choices in support seeking are often ignored. And it remains unknown how teachers seek support for their problem solving. In this research, the pragmatic paradigm and mixed research methods were adopted to answer these questions. A descriptive and bottom-up approach was used by taking a teacher perspective and a holistic view and stressing the individual and situational diff erences between particular problems. Maximum variation samples were selected from three sample schools and one-month-long chat log entries were selected from a teacher?s chat group. Data collected by narrative interview, semi-structured interview and chat log analysis were combined and compared for narrative, thematic, text and descriptive analysis. Th e results revealed that the participants were facing a variety of problems which could be categorized by their primary problem-solving goal. And learning problems were assumed to be most important to them. Th e participants distinguished problems from quasi problems after a three-step process of problem defi nition. Th ey used 13 diff erent kindsof strategies separately or combined for problem solving. Th e fi ve-step process could take place with or without careful planning. Reviewing the success and failure of the participant?s problem-solving attempts, 22 implications were found for teacher?s problem solving. Th ere were many factors aff ecting participant?s strategy selection and use. Th e factors could cause diffi culties for teacher?s problem solving. And the participants had established an ICT-assisted support system to deal with the diffi culties. Th e support system consisted of problems, goals, diffi culties, needs, channels and supports. Based on the analysis of participant?s support seeking, fi ve principles were suggested for building such a system. And there were 16 style indicators that could describe the diff erences between teacher?s problem defi nition, problem solving and support seeking.