The purpose of the developing research of a Problem Based Learning (PBL) e-module is to improve student's science process skills. This research method used research and development (R&D) with a 4D model (Define, Design, Development, and Disseminate). This product was made by using I-Spring Suite 8.0 application. This product was tested on 210 students of class XI Science at Public High School 13 Bekasi, Indonesia on heat and temperature topic. The results of this e-module validation by material experts were 84.06% (very feasible), media experts 93% (very feasible), and learning experts 89% (very feasible). Instrument for improving science process skills used validity testing with product moment and reliability testing with alpha cronbach. To measure the improvement of science process skill is used N-Gain which measure the science process skill between before and after learning on heat and temperature topic. The n-gain score is 0.51 (moderate category). So, development of emodule based on Problem Based Learning (PBL) on heat and temperature topic could improve student's science process skill.