Previous studies in Malang, Indonesia, showed that there were the failure biology learning caused by not only the low students' prior knowledge, but also biology learning model has not improved the students' critical thinking skills yet, which affected the low of cognitive learning outcomes. The learning model is required to improve students' critical thinking skills. Learning model that considered able to solve this problem is a model that combines reading, constructing concept maps, and the implementation cooperative learning type Numbered Heads Together (Remap NHT) in the classroom. This study was quasi experimental research that compared the effect of Remap NHT learning model and traditional learning in biology classroom to improve critical thinking skills at Xth grade students of senior school in Malang, Indonesia. The results showed that the implementation of Remap NHT during biology classroom showed the effect on students' critical thinking skills.