Dexing porphyry copper deposits is one of the largest porphyry copper deposit in the world which is composed of Tongchang，Fujiawu and Zhushahong deposits,it’s located in the southeast of the Yangtze massif and close to the northeast of Jiangxi deep fracture. Based on a detailed analysis of geological characteristics and a study of hydrogen，oxygen，sulfur and lead isotopes in hydrothermal minerals，this paper has discussed the origin of ore-forming fluid and materials and genesis of the Zhushahong deposit. Hydrogen and oxygen isotope analyses indicate that δ18O of quartz in quartz vein of ores range from 8.4‰ to 11.2‰, the corresponding δ18OH2O range from 0.44‰ to 3.14‰, δD of quartz in quartz vein of ores range from -73.2‰ to-56.9‰,the ore-forming fluid in the Zhushahong ore blocks is mainly a mixed fluid of magmatic and meteoric water.The δ34S values of sulfide minerals range from -4.3‰ to -0.9‰ and concentrate around zero value.The narrower distribution range and the lower average of the δ34S value indicate the source of sulphur is deep-source magma sulphur（0±3‰）. Lead isotopic compositions of ores are basically coincident, and 206Pb /204Pb，207Pb /204Pb and208Pb /204Pb ratios of sulfide ores are 18.079~18.643,15.545~15.578 and 38.058~38.5 95．These lead isotope ratios are consistent with those of ore-bearing porphyries but distinctly different from those of the Neoproterozoic metamorphic wall rocks, which indicates that the metals are derived from the porphyries. This may indicates that the lead isotope of sulfides is from the same deep magma source area. The ore-forming fluid in the Zhushahong ore blocks is mainly a mixed fluid of magmatic and meteoric water,the ore-forming materials mainly come from porphyries,Zhushahong deposit is closely related to porphyries.Comparison on isotope characteristics of the three deposits in Dexing porphyry copper deposit：It is revealed that the H-O isotope characteristic of Zhushahong deposits is similar to Tongchang deposit relatively and they may share the similar source of ore-forming fluid. From the Fujiawu in the southeast to the Zhushahong in the northwest, S isotope is from high to low but the basic consistent, the surrounding rock material contamination of Zhushahong could be more than Tongchang and Fujiawu. The Pb isotope of the three deposits shows that the three deposits belong to one metallogenic system and they have the characteristic of crust-mantle mixed lead.