Abstract: Fangshan pluton is a typical Yanshanian middle-to-acid intrusive complex in the east of North China.It has the geochemical characteristics of high contents of Si,Na,Al and Sr,and lack in high field strength elements(HFSE),such as Nb,Ta,and with a high ratio of the LREE/HREE.The composition of Sr-Nd isotope is similar to that of EMI.It is indicated from the geochemical evidences that,the intrusive magma was generated by the partial melting of thickened lower-crust,and the later had been replaced by the forme...