In STEM, learning skills and knowledge are learned simultaneously by students. Things that are different from the STEM aspect will require a connecting line that makes the four disciplines studied and applied simultaneously in learning. The utilization of local cultural characters in the STEM learning model is expected to provide solutions to the low ability of students to solve mathematical problems. Through this local culture-based STEM model, students are invited to get to know the richness of their culture and understand its relationship with mathematics subject matter geometry and learn to find problems, plan solutions, and solve their problems. This study aims to analyze the effect of STEM learning based on Bima's local cultural on problem solving ability. This research is experimental. The samples of this research were 2 class X students of SMA Negeri. The instrument used in this research is a test of geometric problem-solving abilities, in the form of an essay test scattered on each sub-concept and indicator tested. The data analysis technique uses the pooled variance t-test. The results showed that the value of t count is more than t table or tobs = 8,150> t0,05,48 = 2,013 so that H0 is rejected. So, it can be concluded that the Science, Technology, Engineering, and Mathematics (STEM) learning model based on Bima's local cultural affect the problem-solving ability. Based on results, the researchers recommended adopting the STEM based on Bima's local cultural learning model in the teaching and learning process, in addition, further researchers can measure students' abilities on other dependent variables.