The invention relates to a combustion heating system for a Stirling engine. The combustion heating system for the Stirling engine is composed of a straight-shaped gradient lapped type porous medium combustor and a fill type porous medium combustor, which are arranged up and down, wherein the straight-shaped gradient lapped type porous medium combustor comprises a shell, a fuel gas inlet, a pre-mixing chamber, an axial thermal insulating layer, a flame igniter leading wire protective tube, an igniter, a gradient ceramic porous medium layer and a catalyst layer, wherein the fuel gas inlet, the pre-mixing chamber, the axial thermal insulating layer, the flame igniter leading wire protective tube, the igniter, the gradient ceramic porous medium layer and the catalyst layer are arranged in the shell in sequence form top to bottom, the fill type porous medium combustor comprises an external insulating layer, a metal net cylinder arranged in the insulating layer and heating tubes arranged in the metal net cylinder in a central symmetry mode, and the gaps of the heating tubes are filled with metal wires. The combustion heating system for the Stirling engine has the advantages of being stable in combustion, high in combustion efficiency, good in heat transfer performance, good in heat storage performance, stable in working, wide in load regulation range, easy to regulate and less in pollutant discharge, and the effect on improving the fuel gas type Stirling engine working efficiency is remarkable.