Abstract As a part of stereochemistry, cis-trans isomerization is an important organic reaction. In the course of teaching, it is helpful for the students to understand cis-trans isomerization that we show the changes of property and structure between cis isomer and rans isomer. This paper introduces the applications of cis-trans isomerization such as molecular motors of azobenzene molecules, conjugated polyene molecules and aromatic imine molecules. That will enhance the students' interests of learning organic chemistry.