Critical thinking skills are one of the high-order thinking skills that students need in order to keep up with the demands of the 21st century. Critical thinking skills are needed to solve various problems by questioning what they hear and reviewing certain thoughts. The aim of this research is to know students' critical thinking skills through implementation of problem solving models on reaction rate materials. This research used one-group pretest-posttest design with quantitative descriptive type. The subjects were 70 students from the two classes of XI MIPA. The instruments that was used included  observation sheet for implementation of problem solving models and test sheets of the critical thinking skills. The results showed that: 1) the results of observations on the implementation of the problem solving model got good category, 2). critical thinking skills after implementation problem solving model have reached skilled and highly skilled category that was proven by the average score of students at XI MIPA 3 is 80.83 and XI MIPA 4 is 83.10