One of the requirements in teaching process is to develop the thinking of learners. Thus, how an educator could organize teaching activities in order to enable the critical thinking ability of students in high school? Based on the stages of the solving process in the learning process of the student, the expression of critical thinking in each stage, the author would like to suggest educational orientation program following stem system (stem activities) in order to develop critical thinking of students. This article analyses the impact of using stem activities on the development of students in some high schools in mountainous regions in the northern part of vietnam. The results show the development of critical thinking of students through stem activities and some superior suggestions for using stem activities to motivate critical thinking of students in high school. Published under licence by iop publishing ltd.