This article systematically studies environmental problems of waste rock and tailings in the Dexing copper mine. By research on the content of heavy metals in environmental media (water soil plant), this article discusses the environmental effect of heavy metals. Results indicate that the acid wastewater generated from oxidation and leaching from low grade ore was the mainly source to cause the pollution of acid water and heavy metals. There is a heavy pollution of Cu and Zn upriver, where the pH ranges from 3 to 4. But the content of Cu declined from nearly ten thousands μg/g upriver to several hundred μg/g in downstream of Dawu River. And the pH increases to almost 5. The content of heavy metals of the oil in the upstream and middle ranches of the Dawu River is affected by the river, and decreased with the increasing of distance from the bank of the river. The Pb content of rice in the Dawu river area doubled that stipulated by the National Grain Standard. It is presumed that the oxidation depth of surface layer in No.4 tailing sand reservoir is more than 80 cm, while that in No. 1 tailing reservoir is 0~25 cm in depth. The contents of Cr, Cu and Mo in surface layer are higher than those in deeper layer, and decease with increasing of the depth in No. 4 tailing. It is inferred that capacities of producing acid is less than that of acid neutralization, thus Ph value of bottom water of the dam is about 7, which has little effect on adjacent water. The rice from the Shiduntou village No.4 tailing reservoir is high in Cu and Mo, but the soil far from it contains low content of heavy metals. Most of the heavy metals in the two tailings exist in the form of sulfide fractions, which are very stable in reducing environment. The Pb content of the cabbage growing in No.1 tailing reservoir after reclamation was quadruple than that stipulated by the National Vegetable Standard for vegetable, and contents of Cu, Pb and Zn greatly exceeded regional background values.