The invention relates to a phase-change heat accumulation type heat flow sensor mainly consisting of a shell, an upper cover, a lower cover, a back cover, a phase-change heat accumulation body, a constantan circular foil, two nickel chrome wires, a thermoelectric couple, a four-hole aluminum oxide ceramic tube and the like, wherein the surface of the constantan circular foil is blacked, the constantan circular foil and the two nickel chrome wires form a measurement end surface sensitive body, the upper cover is welded with the shell after being welded with the measurement end surface sensitive body; after the phase-change heat accumulation body is screwed in, the lower cover is welded with the shell; and the two nickel chrome wires at the constantan circular foil and the thermoelectric couple are drawn out by the back cover in a fastening manner after passing through the four-hole aluminum oxide ceramic tube. According to the phase-change heat accumulation type heat flow sensor disclosed by the invention, by utilizing the phase-change heat accumulation principle, the working time is remarkably prolonged; by utilizing an E-shaped difference thermocouple, the high temperature resistance of the measurement end surface is largely improved; and by utilizing the thermocouple, a measurement end part is added with a temperature monitoring function and the situations that the measurement end part is molten, burn and the like are avoided.