A resin composition, including (A) a polyimide resin; (B) a pre-polymerised maleimide resin; (C) a thermosetting resin; and (D) a flame retardant. The reactants for use in synthesizing the polyimide resin include an acid anhydride and a diamine, with the diamine including 4,4'-diaminodiphenylmethane and its analogous compounds and polyetherdiamines. The resin composition has the following advantages, a resin film or a prepreg is manufactured from the resin composition comprises a polyimide resin synthesized from a diamine of a specific structure and a pre-polymerised maleimide resin, so as to achieve satisfactory characteristics of circuit laminates, such as a low dielectric constant, a low dissipation factor, high heat resistance, and high adhesiveness, so as to be for use in the manufacturing of metal clad laminates and printed circuit boards.