The Chang’an deposit is one of large gold deposits in the Southern Ailaoshan metallogenic belt in Sanjiang region, and the occurrence of ore bodies is controlled by the brittle fractured zone of Ganhe fault. The comparative study on sulfur isotopic compositions of the ores, wall rocks and magmatic dikes suggests that the sulfur in ore-forming fluid was most probably sourced from the ore-hosted strata and partly mixed with that in the Himalayan period magmatic hydrothermal fluid. It is suggested that the ore lead was sourced from the upper crust with higher maturity, indicating that the lead and other ore-forming elements should be mainly derived from the Devonian dolomite and clastic rocks, the Ordovician sandstone in mining area.