Using minimum temperature data from the second pentad in June to the second pentad in July at 70 observational stations from 1961 to 2001, the Changjiang-Huaihe area's minimum temperature field in Meiyu period is divided objectively into 3 regions by rotated empirical orthogonal function(REOF) method. Based on this,the long-term trend of each region minimum temperature in Meiyu period is analyzed. Results indicate that the minimum temperature field in 3 regions has distinct characteristics of interdecadal change in the recent 41 years，and there is obvious area difference: the long-term trend of minimum temperature went up markedly in northeast area,descended in south area and northwest area.The interannual(interdecadal) variance contribution ,catastrophe feature and variation period in 3 regions exhibit remarkable diversity.