This research aims to determine the POE (Predict, Observe, Explain) learning model in improving students' understanding of concepts in the Chemistry subject at SMA Negeri 1 Gondang. This research method uses a class action research model. The research subjects were 35 students in class X-4. This research has a good impact on students' understanding of concepts, this can be conveyed through the results of cycle I and cycle II research. Cycle I completed 25 students with a completion percentage of 71.4%, while cycle II completed 28 students with a completion percentage of 82.9%. So in cycle I and cycle II there was an increase in students' understanding of concepts in the Chemistry subject. Keywords: POE, Concept Understanding, Chemistry