Being one of the largest gold deposits in Ailaoshan gold belt, the Daping gold deposit is hosted in a ductile deformed and alterated diorite batholith, and is believed to be a typical Cenozoic orogenic type gold deposit. In this study, SHRIMP U-Pb dating of zircon from the diorite batholith was performed, and the result is (773±12) Ma, suggesting that the diorite was a Late Proterozoic batholith, but not a commonly recognized Caledonian rock body. The diorite batholith is a product of large-scale basic to acidic magmatism during the Jinning-Chengjiang epoch, and is corresponding to a period of Gondwana accretion after Rodinian dispersion.