Abstract:This paper tries to trace the source of Cu using the Cu isotope ratio of copper sulphides. According to form sequence, four types chalcopyrite from early potassic alteration, A vein, B vein and D vein were chosen separately. A vein mainly included irregular QuartzK feldspar vein, QuartzAnhydrite vein and Biotite vein, but the B vein were mainly composed by QuartzAnhydritechalopyrite ± molybdenite ± pyrite vein and sericitechlorite vein, and the D vein were mainly plate chalcopyritepyrite vein and pyrite vein. The range of δ65Cu of early potassic alteration is -0.47‰ to -0. 1‰, and the average value is -0.29‰. The δ65Cu ratio of A vein is similar to potassic alteration in range and average value, and cluster from -0.44‰ to -0.31‰. The δ65Cu of B vein is a little higher than A vein, with the range of -0.42‰ to +0.14‰ and the average value of -0.18‰, and cluster between -0.25‰ and -0.18‰. D vein, having the highest δ65Cu range (-0.27‰ to +0.47‰) and average value (-0.02‰), cluster -0.27‰ to -0.05‰. The δ65Cu ratio is consistent with that of magmatic rock on a whole (Zhu et al., 2000, 2002; Maréchal et al., 1999, 2002), which suggest that the Cu is mainly come from magma. Various type samples have significant Cu isotope fractionation, compare to early stage, later fluid relative enriched 65Cu. The isotope fractionation between A vein and B vein maybe related to exsolution of the magmafluid, while the distinction of D vein is more probable result from the mixing of rainwater.