This study aims to develop Student Worksheets electronic based on Project Based Learning (PjBL) on valid, practical and reliable on the Ecosystem subject matter in 10th grade High School. The research uses a 4D model which consists of 4 main stages which include Define, Design, Develop, and Desseminate. The subjects in this study were 23 students of class X MIPA 5 at SMA N 1 Sungailiat in the a…