This study aims to improve the learning process and improve the student’s mathematical problem solving skill (MPSS) by applying Problem Based Learning (PBL) model. The type of this research is Classroom Action Research with two cycles. This research conducted of class VIIB5 MTs Darel Hikmah Pekanbaru on secons semester of academic year 2017/2018 wich consists of 17 male students. The ins…