Abstract: By studying the geology, petrology, petrochemistry and geochemistry of Mesozoic granitoids in Yingkou district, the authors believe the similarities.between Indosuiian granitoids in the studied district and I-type granite defined by Chappell and White,and between the Yanshanian granitoids and S-type granite in petrology.petrochemistry and geochemistry. The forming environment of ihe granitoids and its relationship with gold mineralization are discussed on the basis of the study of petrochemistry,Pb-isotope and gold content. The gold mineralization in this area is believed to be related to Indosinian granitic magmatism.