In order to trace the origin of ore-forming fluid during the complicated mineralization and alteration process of the Zhushahong porphyry copper-gold deposit, the authors analyzed H and O isotopes of quartz from different alteration and mineralization assemblages to evaluate the source and evolution of the ore-forming fluid. Some conclusions have been reached: ① δ¹⁸O and δD values of water show balance with A-type veins (+6.0‰~+11.2‰, -90‰~-101‰),quartz in phyllite (A1), Qtz-kfs veins (A3), B-type veins, straight quartz veins (B1), and Qtz-Moly-Py±Anhy±Cpy veins (B2),suggesting that all the ore-forming fluids were derived from magma; ② δ¹⁸O and δD values of water show balance with the B1-type veins (+6.6‰ and -101‰), implying that fluids inducing propylitic alteration were dominated by the fluid separated from magmatic vapor during exsolution with low density, low salinity and high temperature; ③ Considerable variations of δ¹⁸O in Qtz-Py-Cpy veins (B3) (+4.1‰~+6.0‰) suggest that minor amounts of meteoric water and regional metamorphic water were partially involved in the magmatic water during transforming of K-silicate alteration to feldspar-destructive alteration; ④ During the formation of D-type veins, meteoric water and underground water were infused into the ore-forming fluid-system and mixed with magmatic water (δ¹⁸O:+2.8‰~+4.9‰). Feldspar-destructive alteration which overprinted most of the potassic alteration and part of the propylitic alteration was triggered by the reaction of mixed water with porphyries and phyllite. It is thus held that K-silicate alteration and propylitic alteration accompanying with A-type veins and early B-type veins were caused by the action of magmatic fluid. Meteoric water began being infused into the alteration-mineralization system from the transformation period. However, feldspar-destructive alteration was triggered by the mixed fluid of magmatic water and meteoric water.