This research paper aims to produce a mathematical module with a problem-solving approach to train student's reflective thinking. To find out how to develop modules, there are three criteria must be fulfilled, namely validity, practicality, and effectiveness. Development of module used four stages, namely the initial situation analysis, design development, preparation of the initial product and evaluation. The module developed was assessed by 4 validators, namely 2 lecturers and 2 junior high school teachers. After that, the module was tested twice, the first one is tested on 5 students and then tested on 7 students for testing empirical validity toward the developed modules. Based on the results of the validation of the expert validator on the aspects of subject matter, performance, language and concept evaluation in the module, it can be concluded that the module developed were practical and valid with the average of assessment results validator of 3.31. While the results of the first and second stages of the trial of module, it can be concluded that the module display was interesting for students. In addition, the results of the evaluation of the trial subjects met the minimal completeness criteria so that it could be said that each of the subjects could understand the content presented in the module. From these results it was known that the module was effective. It can be seen in the results of the subject's assessment of the modules were valid and effective with the average of subject's assessment was 3.342.