A thermal-curable resin composition is provided. The thermal-curable resin composition comprises: (A) a thermal-curable resin component, which comprises: (a1) bismaleimide resin; (a2) cyanate ester resin; and (a3) epoxy resin, wherein the cyanate ester resin (a2) and the epoxy resin (a3) are respectively in an amount ranging from 50 parts by weight to 150 parts by weight and from 24 parts by weight to 51 parts by weight per 100 parts by weight of the bismaleimide resin (a1); and (B) a filler, wherein the filler (B) is in an amount ranging from 40 parts by weight to 55 parts by weight per 100 parts by weight of the dry weight of the resin composition; and wherein the resin composition has a dynamic viscosity of not higher than 800 Pa·s after being brought into a semi-cured state (B-stage), and the resin composition has a dissipation factor (Df) of not higher than 0.006 at 10 GHz after being cured completely.