According to the results of the satellite imagery interpretation and field investigation，we study the active features and the latest active times of the Chuxiong-Nanhua fault，the Quaternary basins formation mechanism，and the relations of the fault and the 1680 Chuxiong M6? earthquake. Several Quaternary profiles at Lvhe，Nanhua reveal that the fault has offset the late Pleistocene deposits of the T2 and T3 terraces of the Longchuan River，indicating that the fault was obviously active in late Quaternary. The Chuxiong-Nanhua fault has been dominated by dextral strike slip motion in late Quaternary，with an average rate of 1.6～2.0mm/a. Several pull apart Quaternary basins of Chuxiong，Nanhua，and Ziwu etc. have been developed along the fault. The 1680 Chuxiong M6? earthquake and several moderate earthquakes occurred nearby the fault historically. The Chuxiong-Nanhua fault are the seismogenic structure of those earthquakes，the latest fault movement is in late-Pleistocene，even Holocene. In a larger area，the Chuxiong-Nanhua fault and the eastern Qujiang fault and the Shiping fault composed a set of NW treading oblique orientation active faults，and the motion characters are mainly of dextral strike slip. The motion characters，like the Red River fault of the Sichuan-Yunnan Rhombic Block southwestern boundary，is concerned with the escaping movement of the Sichuan-Yunnan Rhombic Block.