The invention discloses a synthesis method of flower-like structure polyimide. The method comprises the following steps of (1) carrying out esterification reaction on a dianhydride monomer and alcohol to obtain aromatic tetrabasic acid dibasic ester; (2) obtaining a pyrazinecarboxamide salt of dibasic ester from a dianhydride monomer and the aromatic tetrabasic acid dibasic ester; (3) carrying out spray drying on the pyrazinecarboxamide salt of the dibasic ester to obtain a white powder solid; (4) adding the white powder solid to dihydric alcohol, raising the temperature and carrying out heat preservation reaction in a nitrogen atmosphere to obtain a product a; (5) centrifugally separating the product a, and washing the solid product by adopting an eluent; and (6) drying the washed solid product in the nitrogen atmosphere to obtain the flower-like structure polyimide. The method is a novel method and way for simply, efficiently and quickly preparing the flower-like structure polyimide, and the method has important application value.