Abstract: Lake groups in the Songnen Plain are low plain lake groups, which are located in the temperate semihumid area in China. They are characterized by small area, shallow basin, thick density and various types.In the try for classifying comprehensively the lake groups, a classification system is developed based on three main factors, i. e. forming cause, water quantity and water quality. The most internal character can be concisely grasped through three principal indexes and three auxiliary indexes of the three main factors. A simple or complicated changeable path is put forward for further analyzing and outlining these basic types, in the meantime, it’s linking up easily with the classification system of the single factor.According to the regional environment, the regional differences of the type composition and the principal types, the lake groups in the Songnen Plain can be divided into 6 sub-regions.