Abstract
This study aims to determine the effect of problem based learning model with debriefing prior knowledge of the science process skills of learners. This research is a quasi experimental research using non-equivalent control group design. The population in this study is all students of class XI IPA SMAN 1 Montong Gading. The sampling of the research using saturated sampling technique, so that the selected class XI IPA 1 as the experimental class will be given treatment in the form of problem-based learning model with initial knowledge knowledge and class XI IPA 2 as the control class to be given treatment in the form of problem-based learning model. Data collection of science process skills using observation techniques on the observation sheet. Hypothesis test using t-pooled variance test obtained tcount value is greater than ttable. The result of the research shows that the use of problem-based learning model with prior knowledge sharing influences the science process skill of SMA students.