The invention belongs to the technical field of polymer modification, and provides a thermal stabilizer composed of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzene Diformamide and zinc compound, wherein the zinc compound is selected from zinc carboxylate, zinc carbonate, zinc titanate, zinc molybdate, zinc ferrite, zinc sulfate, zinc phosphate, zinc oxide, zinc borate, zinc halide Any one or a mixture of several. Compared with the prior art, the heat stabilizer provided by the present invention can: give the resin base material good long-term heat resistance; itself has better dispersion in the resin; improve the floating of the surface of the glass fiber reinforced injection molded part fiber condition; long-term injection molding does not corrode the mold; does not affect the CTI value (relative tracking index) of the product.