Based on large sets of monitoring data, this paper analyzed the seasonal variation and spatial difference in four main parameters of water quality at Lake Liangzi, examining the water quality in three different spatial levels in individual sampling locations, subdivided lake areas and the entire lake. The major pollution parameters of COD_Mn, total nitrogen(TN) and total phosphorus(TP) were examined at the East Lake Liangzi, COD_Mn, TN and ammonia nitrogen at the Lake Niushan, COD_Mn and TN at the West Lake Liangzi. Results showed that there were significantly spatial and seasonal changes. Pollution was relatively serious in summer and fall as COD_Mn was high and in winter as TN was high, while the pollution was relatively light in spring. The results are helpful to better understand the spatial and seasonal patterns of water quality in Lake Liangzi and to find practical strategies for water quality protection and management.