One of the factors that can support successful learning activity is the use of learning models according to the objectives to be achieved. This study aimed to analyze the differences in problem-solving ability Physics student learning model Inquiry Training based on Just In Time Teaching [JITT] and conventional learning taught by cooperative model so that it can be seen whether there is influence learning model Inquiry Training based Just In Time Teaching on problem solving ability of students in General Physics II study. This research is a quasi-experiment study, population are students of program Physical Education Department of Physics, State University of Medan. Sample selection is done by cluster random sampling. The instrument used was a test problem solving abilities. Data was analyzed using ANOVA one-way test. Results of testing the hypothesis showed that H[subscript a] accepted that there are differences in problem solving capabilities of physics students through learning model Inquiry Training based JITT and cooperative learning model so that it can be concluded that there is influence learning model Inquiry Training based JITT against problem solving ability of students in learning physics General physics II.