Abstarct: Pyrite oxidation as ubiquitous mineral phase in porphyry copper deposits results in producing acid mine waste. Chemical composition, mineralogical and texture characteristic of Pyrite and also accompany with other minerals Influence on oxidation rate of Pyrite and Release of toxic elements from this mineral. In this thesis will be discussed study the chemical composition of Sarcheshmeh Porphyry Copper Mines Pyrites. Mineralogical studies on about 150 polished sections from the dumps, ore body and tailings samples and analysis was done about 200 points of pyrite. The emportant minerals identified in Waste dumps, ore body and tailings were respectively: pyrite, chalcopyrite, sphalerite, galena, covellite and magnetite; pyrite, chalcopyrite, bornite, chalcocite, covellite, Digenite and molybdenite; pyrite, chalcopyrite. Chemical composition analysis in above samples by Electron microprobe analysis (EMPA) was used. Due to the results of electron microprobe analysis range of element concentration in Waste dumps, ore body and tailings Pyrites is as follows: Iron(45.68- 48.63)wt%, sulfur( 49.48- 55.28)wt%, arsenic( <100- 8400)ppm, copper (<100- 11300)ppm, nickel( <100- 2900)ppm, cobalt( <100- 1900)ppm, cadmium( <100- 900)ppm, antimony(< 100- 500)ppm. mercury in Pyrites of Waste dumps is (<100- 2500) ppm. The present Pyrite is included a large amount of arsenic and mercury that are volatile and highly toxic elements. This Element can result in polluting the area. Also, the source of Arsenic in Waste dumps Pyrites in addition to pyrite, minerals sulfosalts as well.