Abstract: The Melmeg Lake groups are located on the right side of backward position of the Nenjiang River. Here is lower physical features, lake, marsh and wetland are linked, the aquatic plants are flourishing, here provides an ideal house for birds. e. g. red-crowned crane. The lake-level change and eco-environment change are mainly decided by the change of rainfall and river-level of fifty years. There is a tendency to warm up in climate of Songnen Lake region in fifty years, the fluctuation range of water-level gets bigger, the eco-environment becomes fragile. The human activities e. g. water conservancy facilities, agricultural cultivation and industrial pollution give rise to lake groups and their environment change which include positive and negative sides. Although the intensity differs from the space and time, yet the overall tendency is that lake-level drops and ecological environment gets worse.