Machangqing complex is an important part of alkali-rich porphyry belt in western Yunnan Province. According to the geological features of the enclaves, the author analyzed the zircons from enclaves with the LA-ICP-MS and obtained a U-Pb weighted average age of (35.13±0.23) Ma (MSWD=0.64). Studies show the Machangqing alkali-rich porphyry is the mixture of crust-derived and mantle-derived magma enclaves and their host rocks have the similar magma evolution process and the injection of mantle-derived magma is a key factor to the ore-formation of this series magma.