The invention discloses a method of increasing perovskite film crystallinity. The method comprises the following steps of mixing lead iodide and methyl ammonium iodide and then dissolving into N, N-dimethyl formamide and dimethyl sulfoxide; mixing zinc iodide and the methyl ammonium iodide and then dissolving into the N, N-dimethyl formamide; and mixing two solutions according to a certain proportion, and then through spin coating annealing, acquiring a high-quality perovskite spin coating film. Crystallinity of a perovskite layer manufactured in the invention is good, a coverage rate is high, flatness of a perovskite film surface is greatly increased, a reaction condition is easy to control, repeatability is good and equipment is simple. The method possesses good operationality. Manufacturing cost of the perovskite film is effectively reduced. And the method can be popularized and applied to actual production.