Abstract: Phosphogypsum produced by phosphorus chemical industry is the bulk industrial solid waste. The impurities would reduce the performance of β−hemihydrate gypsum that was prepared from phosphogypsum. In this study, phosphogypsum was purified by flotation method, and the performance of β−hemihydrate gypsum prepared from phosphogypsum before and after purification was compared. The results showed that the fine slime and organic impurities were removed by reverse flotation with methyl isobutyl methanol as foaming agent, and the dihydrate gypsum was floated by dodecamine. Compared with phosphogypsum ore, the whiteness and purity of the concentrate increased from 19.4% to 41.1% and 73.12% to 96.41%, respectively. The 2−hour flexural strength, compressive strength and 3−day dry compressive strength of β−gypsum that was prepared from phosphogypsum concentrate were 22.8%, 14.1% and 24.1% higher than those was prepared from raw ore, respectively. Whiteness increased from 27.8% to 46.3%. Flotation purification can significantly improve the performance of phosphogypsum in β−gypsum preparation.