The 34 focal mechanisms are selected from Global CMT and publications during 1978-2016 and analyzed. After weighting each focal mechanism according to its magnitude,the present tectonic stress field in the central region of Sichuan-Yunnan blocks is inverted using grid search method. The results show:The focal mechanisms primarily show strike-slip types in the central region of Sichuan-Yunnan block,but normal fault type in the west. The regional stress field is nearly NW compression and NE extension;the stress shape factor is estimated to be 0.1. The extensional axis of the stress field is nearly horizontal,which shows lateral extension action in this area. Lower stress shape factor suggested nearly biaxial compressional stress in NW-SE and up-down direction and larger NE-SW extensional stress. The stress state results from two effects:(1)the NW-SE compression and NE-SW extensional strike slip stress state due to the Qinghai-Tibetan Plateau's material eastward flowing and the blocking of the Southern China Block.(2)NEE-SWW extension in the shallower crust resulted from the subducting in the depth of the Burma Arc. Both the effects contribute to the occurrence of strike-slip and normal faulting earthquakes.