Preparation method of tacrolimus crude crystal

The invention provides a preparation method of a tacrolimus crude crystal. The preparation method comprises the following steps: acidifying a tacrolimus fermentation liquor, and carrying out resin adsorption; carrying out filtering, removing the supernate, and then carrying out washing with water to remove mycelia to obtain resin rich in tacrolimus; then carrying out soaking with acetone under stirring to obtain a tacrolimus soaked solution, and carrying out reduced pressure concentration to obtain a concentrate; adding an organic solvent, carrying out stirring, removing solids, and allowing the obtained solution to stand to remove the water layer so as to obtain an organic solution; adding a saturated sodium bicarbonate solution, carrying out washing, removing the water layer to obtain anorganic phase, carrying out washing to neutrality by using purified water, then carrying out layering to obtain an organic solution layer, and finally, carrying out reduced pressure concentration onthe organic solution to ob