The Lamasu copper deposit was once an important prospected area in Xinjiang. There are several hypotheses about the genesis of the deposit, e. g. skarn type, strata-bound type and porphyry type. According to a great number of sulfur, lead, oxygen isotopic and other data, the writers believe that it is a typical skarn type copper deposit. The main mineralization is a large stratoid copper orebody and the main sulfide is pyrrhotite (chalcopyrite is subordinate). As the copper-bearing hydrothermal solution flowed through the carbonaceous limestone bed rich in collof orm pyrite and framboidal pyrite, sulfur f ugacity increased, and thus chalcopyrite was precipitated and high-grade copper orebody was formed.