The invention discloses a high-temperature high heat flow simulator for spacecraft vacuum heat tests in a space environment simulating chamber. The simulator mainly comprises infrared light arrays, a high-temperature insulation component unit, moving units, a temperature measuring unit and a temperature controlling unit. A plurality of infrared lights in the infrared light arrays are provided with reflective screens, the infrared lights are arrayed and combined to form the infrared light arrays according to requirements of heat flux density and uniformity, baffles surround the periphery of the infrared light arrays, high-temperature multi-layer insulation components are mounted among the infrared lights, a mounting baseplate and the baffles, and a high temperature region is limited in region formed through specimen irradiated face and the infrared light array high-temperature insulation components. According to the high-temperature high heat flow simulator, by means of unique design of the infrared light arrays and the high-temperature insulation components, technical difficulties of high-temperature high heat flow simulation when vacuum heat tests are performed on a spacecraft are solved, high-temperature high heat flow space environment can be simulated when vacuum heat tests are performed on spacecrafts in series of deep space exploration and space shuttles, and the spacecrafts can be tested.