In this work, the solubility of phosphogypsum(PG) in water and saturated lime solution was determined in experiments carried out at different temperatures from 10 to 50°C. The solubility of natural gypsum(NG) was also studied at an attempt to find out differences in solubility between PG and NG due to the effect of impurities. The results show that in pure water media, PG dissolves more rapidly than NG at early time, and then equally with NG. With increasing the temperature of water, the dissolution rates PG decreased while that of NG increased. In saturated lime solution, compared with NG, the solubility of PG was distinctly influenced due to the existence of impurities. Possible reaction among soluble impurities and calcium ion retarded the dissolution of calcium sulfate dihydrate.