The Caohai peat is located in the eastern of Yungui Plateau, approximately between 26044'~27°01'N, 104°00'~104o30'E,with an area of about 50km2. The Caohai is typically subtropical and subalpine area in our country, because of the double influence of the southwest monsoon and the East Asian monsoon. It is sensitive to the climate change,making it an ideal region for the climate change research of the southwest of China during the Holocene. A peat profile NT (26°52'N, 104°15'E; 2202m a.s.1.,339cm in depth) was digged in April, 2011, in Caohai,Weining County,Guizhou Province,located in the northeast of Caohai Basin,and 339 soil samples were collected from the bottom to the top of the profile at every 1cm. AMS ~(14)C was dated by the residual seed extracted from peat samples. In this study, the climatic evolution since 7.1 cal.ka B.P. in Caohai area was reconstructed by the records of humification and loss on ignite (LOI) of the NT profile. The results showed that the climatic evolution since 7.1 cal.ka B.P. in Caohai area could be divided into three stages. The first stage was warm and wet during the period of 7.1 ~4.5cal.ka B.P., and the climate fluctuated gently. The second period, from 4.5cal.ka B.P. to 2.4cal.ka B.P., could be further divided into sub-stages: peat humification and ignition loss appeared two obvious drops since 4.5cal.ka B.P.,the temperature began to bounce back after 3.8cal.ka B.P.. During the period of 3.1~2.4cal. kaB.P.,it showed a warm-wet phase continuing about 700a. Since 2.4 cal.ka B.P. the climate has been cold and dry than the the former two phases. The climatic evolution progress in the Caohai area is highly unstable and has undergone century-millennial scale through all three periods. There has been seven cold events that happened in about 6.5 cal.ka B.P., 6.0 cal.ka B.P., 5. Ocal.ka B.P.,4.2cal.ka B.P.,3.8cal.ka B.P., 1.9cal.ka B.P. and 0.9cal.ka B.P. since the Middle Holocene. These evidently correspond with Hongyuan peat, Dongge cave stalagmite, Hani peat, and with deep-sea sediments in high latitude regions in the Northern Hemisphere. The above results show that the climatic change in the Caohai area since the Middle Holocene is consistent with the global climatic change. Comparing the Caohai peat in transition zone with the Hongyuan peat in the southwest monsoon area and Hani peat in the East Asian monsoon region, the high latitude driving (North Atlantic Oscillation) and the low latitude driving (El Nino) in the eastern monsoon region were stronger than the southwest monsoon area, otherwise the southwest monsoon area was affected by the low latitude driving than the high latitude driving.,and the Caohai peat in transition zone was driven by the high and the low latitude factor at moderate levels. Using the power spectrum analysis, the remarkable cycles of the climate variations is 1108a, 405a, and 205a, which correspond with the periodicity of the solar activities. Therefore, it reflects that the solar activity and El Nino are important driving forces to the climate change in the southwest monsoon area.