The present invention discloses a method for producing the alpha-calcium sulfate hemihydrate bone graft, which comprises the following steps: mixing calcium sulfate dihydrate and deionized water to produce calcium sulfate dihydrate paste; stirring and heating the calcium sulfate dihydrate paste at least 160° C. within 100-350 psi to produce the conversion calcium sulfate hemihydrate, filtering the conversion calcium sulfate hemihydrate with high temperature to produce the filtered calcium sulfate hemihydrate, and washing the filtered calcium sulfate hemihydrate by absolute alcohol to get the alpha-calcium sulfate hemihydrate bone graft. The present invention does not use any catalyst, possesses a high purity, high mechanical strength, and good biocompatibility, facilitates bone growth and angiogenesis, requires only 31° C., the highest temperature, during the curing process. It makes the present invention more secure in the biomedical applications.