The Bijective method (BM) is an interesting method to solve some counting problems. However, in Vietnam there are few articles mentioned on this method and there is not any author mentioning how to teach this method for good and excellent students of high schools (HS). So, the authors would like to share teaching experience of concepts on mapping, injective, surjective and bijective functions. Simultaneously, the authors analyze some examples on applying the bijective method to solve some counting problems in order to help students understanding more about this method.