Abstract: The solid wastes from mining activity include mullock, mine tailing and smelting slag, which are piled in the open air and will have great impact on the surrounding environment after long-term natural weathering. In this paper, mullock, mine tailing and smelting slag are sampled by taking Panzhihua V-Ti magnetite mining activity as an example to study the releasing mechanism and the environmental effect of heavy metals in these solid wastes under the conditions of different pH values and granularities through the lixiviating experiment. The results show that the lixiviating rate of most elements becomes higher under lower pH value and lower under alkaline condition, but the lixiviating rate of V and Cr in mullock and that of Ti in slag become higher under alkaline condition; the lixiviating rate of thin samples is higher than that of thick ones under the same pH condition, but the lixiviating rate of Ti, V, Co and Cr under the pH value of 12 and that of Ti and Cu under the pH value of 1 are abnormal, that is, the lixiviating rate of thick samples is higher than that of thin samples. The heavy metals released by solid water will certainly have impact on the surrounding environment, so they should be given closer monitoring.