Based on daily precipitation, mean air temperature, maximum and minimum air temperature, wind speed and direction (four times a day) data during 1961-2018, and hourly precipitation data during 1978-2018 from 6 national meteorological stations around the Poyang Lake as well as the reanalysis data of European Center during 1979-2018, the climate difference between the east and the west side of the Poyang Lake caused by the cold-heat source effect on different time scales was analyzed. The results are as follows: (1) There was an obvious cold-heat source effect in the Poyang Lake. The diurnal temperature range in the Poyang Lake area was 2-4 ℃ smaller than that in mountainous areas, and the high temperature days was half of that in other areas of the same latitude in Jiangxi Province. (2) The precipitation in the Poyang Lake was also less than other areas of Jiangxi. The precipitation in the east and the west side of the lake presented the cyclical fluctuation in a year, there were more precipitation from August to October in the west side of the lake, while there were more rainfall in other months in the east side of the lake, the difference was obvious especially in middle of winter and summer. (3) There were differences of precipitation between the east and the west of the lake at day and night. The precipitation in the east of the lake was more obvious at night in January, while in September it was more obvious in the west of the lake at day. (4) Lake-land wind existed in the Poyang Lake. The average wind speed at 02:00 BST in January at Yongxiu station in the west side of the lake was higher than that of Duchang station in the east side of the lake, and the west wind component occurred more. In August, the average wind speed at Duchang station was higher than that of Yongxiu station at 14:00 BST, and the south wind occurred more frequently. (5) Compared with 14:00 BST, the atmospheric ascending motion was more obvious at 02:00 BST in the main area of the Poyang Lake in January, the near-surface wind field converged. While compared with 02:00 BST in August, subsidence movement was more obvious at 14:00 BST, and near-surface wind field diverged.