The invention discloses film-grade polyphenylene sulfide resin. The film-grade polyphenlene sulfide resin is mainly prepared from sodium sulfide, alkali metal hydroxides, a catalyst, p-dichlorobenzene and meta dichlorobenzene which are reacted in the environment of 220-260 DEG C for 3-6 hours. The invention further provides a preparation method of the resin, and the method comprises the steps that 1, the sodium sulfide and the alkali metal hydroxides are stirred and dispersed in solvent NMP, and after dehydration is conducted, a mixture is obtained; 2 the solvent NMP, the catalyst, the p-dichlorobenzene and the meta dichlorobenzene are added to the mixture, heating is conducted to make the temperature range from 220 DEG C to 260 DEG C to conduct polymerization for 3-6 hours, and the film-grade polyphenylene sulfide resin is obtained. According to the film-grade polyphenylene sulfide resin, an adequate amount of the meta dichlorobenzene is added when the PPS resin is compounded by taking the p-dichlorobenzene as the raw material, a linear type polyphenylene sulfide molecular chain is changed into an elastic polyphenylene sulfide molecular chain with a bend structure, and the transverse tensile capacity of a polyphenylene sulfide film prepared from the resin is enhanced. In addition, the weight-average molecular weight of a polymer is controlled by controlling the reaction temperature and the reaction time, and the thickness of the formed film is more even.