Abstract: Using the temperature data from China Meteorological Administration, the NCEP/NCAR reanalysis data, the monthly mean Hadley SST as well as some indices from the CPC(NOAA), we have analyzed the variations of the summertime temperature anomalies in the middle and lower reaches of the Yangtze River. The results show that the summertime temperatures vary according to the three principal modes: the first mode changes with a uniformly signed structure spatially, the second with an opposite phase meridionally, and the third with an opposite phase zonally. And they are respectively a part of the anomalous temperature distributions in the whole country. All of the three modes change on both interannual and decadal timescales. The 2-5 year periodicities are the prominent variations in these three modes. On interannual timescale, the aforementioned three modes are related to the different circulation anomalies whose vertical structures are barotropic. The maintenance of the anomalous circulations related to the three patterns are found to be related to respectively the wave train originated from the Atlantic and propagating through the Arctic areas, the perturbations propagating easterward along the Asian jet from the Mediterranean region, and the Arctic Oscillation. Besides, the first two modes are closely related to the wave train of the P-J pattern. Concerned with the CPC index, the PC1 is negatively and well correlated with the Nino3 index with the Nino3 index leading 1 season to the PC1. The correlation coefficient between the PC2 and the Nino3 (Nino4) index is significant if the Nino3 index is two (zero) seasons leaded to it. And the PC3 is also well correlated with the Nino3 index simultaneously especially when the Nino4 is leading to the PC3 by 3 seasons. These results mentioned in the present article are helpful for us to better understand the variation features of summer climate in the middle and lower reaches of the Yangtze River, and to find clue to the prediction for the extremes of summertime temperatures.