Abstract: Genetics is a basic and important theoretic course in the life sciences and is the one of the most dynamic subjects. The article introduces the constructivism learning theory and has the fundamental reform in the teaching genetics for undergraduates. It will establish broadminded and various teaching methods for the both theory and lab work and multiple examination systems. Using different teaching media, the abstract concept can be made more viewable and the good learning environment is created for students, so that there are more interactions and co-operations between students and teachers. .Eventually, the reform will help students construct their basic genetics knowledge in a better learning environment.