A phase change exchanger for airborne intermittent type high heat flow density surface cooling comprises a box shell. The interior of the box shell is divided by a first partition plate and a second partition plate into three sealed cavities including an upper interlayer, a middle interlayer and a lower interlayer from top to bottom. A first cold fluid inlet and a first cold fluid outlet are formed in the side wall of the upper interlayer. A spiral coiled pipe with a hot fluid inlet and a hot fluid outlet and a phase change material are horizontally arranged in the middle interlayer. A second cold fluid inlet and a second cold fluid outlet are formed in the side wall of the lower interlayer. A first bent plate and a second bent plate are horizontally arranged in the upper interlayer and the lower interlayer respectively. According to the phase change exchanger, by means of the characteristic that a high heat flow density surface intermittently works, heat energy on the high heat power surface is stored and released through the phase change material; the phase change exchanger is compact in structure, small in size, large in heat exchange area and high in heat absorption and release capacity. The invention further discloses a working method of the phase change exchanger for airborne intermittent type high heat flow density surface cooling.