Located at the joint of western margin of the Yangtze plate and eastern side of the NWtrending Ailao Mts.—Jinsha River major fault, the Machangqing intrusives is a part of alkalinerich intrusion belt of the Ailao Mts.—Jinsha River. The Machangqing intrusives mainly consist of granite porphyry, monzonite porphyry and syeniteporphyry.The compositions of the rocks are riched in alkaline, aluminum, potassic, large ion lithophile elements（Rb, Sr, Ba,Th and U） and light rare earth elements, depleted in Ta, Nb and Ti, with “TNT” negative anomaly. The value of LREE/HREE ranges from 8.04 to 23.99， δEu from 0.72 to 0.88，is no conspicuous Eu anormaly；n(87Sr) / n(86Sr) ranges from 0.7072 to 0.7086，averaging 0.7080, higher than present mantle value (0.7045)；n(143Nd)/n(144Nd) varies in the range of 0.5121～0.5124，averaging 0.5123， lower than present mantle value (0.512638)；ISr varies in the range of 0.7061～0.7075，averaging 0.7070；(Ndvaries in the range of -3.1～-10.2，averaginjg-6.8. The Machangqing intrusives are neither traditional alkaline rocks with some dark alkaline minerals nor typical Atype granite, but alkalinerich intrusions. The magma of the intrusives is derived from the mixture of crust—mantle, as being called EMⅡtype. The intrusives show the characteristics of crust—mantle mixture, resulting from mixing in the mantle source with the crust subduction formed in a postcollisional intraplate.