Abstract: In view of the high cost and high risks in conducting full-scale physical experimental validation for space pumped single-phase fluid loop, as well as the challendges in the equivalent simulation of space radiation and heat dissipation behavior in atmospheric environment, a hardware-in-the-loop simulation (HILS) test platform architecture based on CAN bus was proposed. By utilizing a space thermal model to replace some physical entities and integrating ground-based method for equivalent validation of single-phase fluid loop radiator in ambient pressure, the rapid and reliable online validation of the dynamic characteristics of the control system for the space pumped single-phase fluid loop was achieved. The results show that the temperature control accuracy of the system can generally reach ±0.5 ℃ under three working conditions. There is little difference in the temperature control performance between conventional PID and neuron PID. The impact of short-term transient high heat flux on the temperature of the control point of main circuit does not exceed 1 ℃. The proposed research may provide a new technical approach for the development and validation of space pumped single-phase fluid loop control systems.