The invention relates to a method and device for regulating and controlling the temperature of a radiation block in a vacuum environment, a computer storage medium and a background radiation simulator. The method includes the steps that a temperature sensor measures a real-time temperature signal of a radiation plate, and a temperature control module acquires the real-time temperature signal measured by the temperature sensor, compares the real-time temperature signal with a temperature control target range and circularly executes temperature judgment according to a fixed cycle to generate a power supply control instruction and a liquid nitrogen control instruction; a power supply controller receives the power supply control instruction of the temperature control module, completes power supply voltage control and outputs power supply voltage to a heating film; a liquid nitrogen controller receives the liquid nitrogen control instruction of the temperature control module, completes liquid nitrogen supply control, and outputs liquid nitrogen of a liquid nitrogen source to a heat sink; the heating film heats the radiation plate according to the power supply voltage; the heat sink cools a lining plate, the heating film and the radiation plate according to the input amount of the liquid nitrogen. According to the method and device for regulating and controlling the temperature of the radiation block in the vacuum environment, the computer storage medium and the background radiation simulator, a closed-loop control channel is utilized, and a wide-range temperature regulation andcontrol effect in the vacuum environment is achieved.