With　the　rapid　development　of　industry,　the　emission　of　industrial　by-product　gypsum　has　increased　sharply.　At　present,　the　stacking-landfill-based　treatment　method　not　only　wastes　a　lot　of　resources,　but　also　seriously　pollutes　the　ecological　environment.　Therefore,　large-scale　consumption　of　industrial　by-product　gypsum　is　imminent.　Among　the　gypsum　phases,　α-hemihydrate　gypsum　has　excellent　properties　which　has　been　widely　applied　in　various　practical　projects.　Using　industrial　by-product　gypsum　to　prepare　α-hemihydrate　gypsum,　realizing　the　high　value-added　utilization　of　gypsum,　has　great　application　value.　Whereas,　the　pretreatment　method　of　industrial　by-product　gypsum,　the　preparation　method　of　α-hemihydrate　gypsum　as　well　as　the　crystal　form　regulation　are　important　influencing　factors　for　the　preparation　of　α-hemihydrate　gypsum.　Based　on　this,　in　this　paper　the　industrial　sources　of　α-hemihydrate　gypsum　and　the　key　technologies　of　preparation　at　home　and　abroad　were　reviewed.　The　effects　of　pretreatment　methods　such　as　physical　and　chemical　methods　on　the　purification　of　industrial　byproduct　gypsum　were　summarized,　the　crystallization　mechanism　of　α-hemihydrate　gypsum　was　discussed,　and　different　preparation　methods　were　compared　and　evaluated.　The　crystal　form　control　methods　such　as　stirring　and　ball　milling　were　reviewed,　the　effect　of　crystal　modifier　on　the　crystal　form　of　α-hemihydrate　gypsum　was　analyzed,　and　the　crystal　transformation　mechanism　was　pointed　out.　©　2025　Chemical　Industry　Press　Co.,　Ltd..　All　rights　reserved.