Abstract: Based on the heat transfer and dissipation in cases of high power, multi heat sources and highly non-uniform power density for some special satellite payload, a 3D-printed shape follow-up minichannel thermal collector is developed. In view of the assessed reliability of the numerical simulation method to predict the flow and heat transfer performances of the complex 3D-printed minichannel thermal collector, the effects of the flow rate, the inlet temperature, the thermal power and the gravity on the laminar heat transfer characteristics of the thermal collector are studied by the numerical simulation and the experiment, respectively. The empirical relations between the friction factor and the Nusselt number for the thermal collector are obtained, and the structure of the minichannel thermal collector is thus optimized. It is shown that with the increase of the flow rate, the pressure drop of the thermal collector increases approximately linearly, and the increase rate of the total heat transfer coefficient decreases gradually. Increasing the inlet temperature or the thermal power would reduce the pressure drop and increase the total heat transfer coefficient of the thermal collector. Gravity has little effect on the pressure drop and the total heat transfer coefficient of the minichannel thermal collector.