This paper reports a study on improving students’ interest of problem solving model with or without game-based learning (GBL) in learning mathematics. Ninety-one students of grade eight (M = 13.9; SD = 0,5 year) from Indonesia were randomly allocated to participated in the study. The study employed a field experiment with a pretest-posttest control group design, therefore students studied mathematics of two condition. These two condition include problem solving that was developed on game-based learning (PS+GBL) and basis of the textbook (PS+TB). Three questionnaire were used in this study, one for assesing prior of students’ interest (pretest); post-testing for knowing students’ interest after being given treatment; and paper questionnaire to gain information about students’ preferences for the different learning conditions. The results show that the game-based learning improved students’ interest compared with textbook oriented that they regularly use in learning mathematics problem solving. Therefore in this paper also shown some description related to the interface about game-based learning that used in this study.