This research is a qualitative descriptive research with ethnographic type. The subjects of this study were teachers, trainers and students of Pencak Silat Blebet Bali. This art is one of the arts of Pencak Silat which was very typical for the Balinese people, especially Pegayaman Village. This martial art was passed down from generation to generation from the ancestors in Pegayaman Village. The term Pencak Silat blebet has the meaning of meeting, friendship and famly. The rattan/blebet weapon used indicates that friendship and relations between religious communities continue to be in harmony and there is no division, as is the case with rattan/blebet which has a strong texture and is not easily damaged. The research instruments used were observation, interviews and documentation. The results of this study indicate that many mathematical concepts of geometry are contained in the Pencak Silat Blebet Bali. The mathematical concepts of geometry include: the concept of triangles, trapezoids, parallelogram, the relationship of lines and angles. These mathematical concepts are very relevant to be applied in realistic mathematics or contextual mathematics learning in elementary and junior high school classes.