Abstract: Based on the multivariate empirical orthogonal function (MV-EOF) analysis, a decadal turning of the East Asian careulation in the past 30 years was revealed.In this context,the decadal change of the South China precipitation and its possible mechanism were investigated,conclusions are as follows; (1)The first mode of spring and the second mode of summer for the Fast Asian circulation are both of a decadal shift in mid-1990s.(2) The two decadal shift leading modes are closely related with an obvious out of phase seasonal decadal rainfall change in spring and summer over South China; the rainfall reduced in spring and increased in summer.(3) The atmospheric heat source (Q1)over the Tibet Plateau region in spring and the Lake Baikal region in summer are both decadal changed in mid-1990s.(4)The decadal weakening of the Tibet Plateau heating which do pressed the southwesterly on its southeast side mainly caused the reducing rainfall in spring over South China.While the decadal changing of the dipole distribution of the atmospheric heat source in summer over Lake Baikal excited an anomalous anticy clone, which hindered the summer rain belt moving northward,resulting in increased rainfall in summer over South China.