According to the monthly monitoring data on water quality (permanganate index(COD_Mn), ammonia nitrogen(NH₃-N), total nitrogen(TN), total phosphorus(TP)) and meteorologicalogy (mean temperature, precipitation, sunshine duration) from 2007 to 2014, the change pattern of water quality in Lake Dianshan and the impacts from meteorological factors were analyzed. Results showed that:1) Mean temperature and sunshine duration had significantly negative impacts on NH₃-N and TN. Mean temperature had significantly positive impacts on TP. Precipitation diluted and had negative impacts on COD_Mn, NH₃-N and TN. 2) Water quality exhibited seasonal variations under the meteorological impact. Higher values of COD_Mn appeared between April and September, while lower values between October and March. NH₃-N, TN peaked between February and April, reaching lowest value between July and October. TP peaked during July and August, while lower values appeared between October and May. 3) COD_Mn, NH₃-N, TN, TP showed downward trends.