Abstract: Tectonically, the northwestern Yunnan area may be separated into 3 first-order tectonic units, 10 second-order tectonic units and 25 third-order tectonic units. From west to east, the above-mentioned 10 second-order tectonic units consist dominantly of the Dulongjiang arc-basin system, Bingzhongluo block, Mode suture zone, Chongshan block, Lancangjiang volcanic arc, Lanping block, Yunling continental-margin arc, Jinshajiang suture zone, Xianggelila block and Garze-Litang arc-basin system. The boundary faults are assembled, from west to east, by the Gaoligongshan fault, Bangdang fault, Fugong fault, Biluoxueshan fault, Jicha fault, Deqen-Xuelongshan fault, Yangla-Dongzhulin fault, Jinshajiang fault, Xianggelila fault and Sanjiangkou fault. The classification scheme proposed in this paper represents the new progress and refinement of the tectonic units in northwestern Yunnan.