The invention discloses a cast manufacturing method for large plaster mold precise casting, which is used for solving the technical problem that bubbles exist in slurry by the existing zinc aluminum alloy plaster mold casting manufacturing method. The technical scheme comprises that by a roasting process of increasing the content of beta type hydrated gypsum in the plaster formula to optimally matching quartz powder, and gradually heating, the manufactured plaster casting has no bubble attachment, cracking or other phenomena in the grouting and roasting steps.