Ultra low orbit satellites generally refer to satellites that operate at an altitude of 300 km or below and above 150 km. Deploying satellites in this orbit can achieve small aperture high-resolution reconnaissance. The height of the ultra-low orbit decreases, the influence of Earth's albedo on the remote sensor increases. The thermal flow environment outside the orbit is complex and harsh. And the high sensitivity brought by the large compression ratio makes the optical tolerance twice as strict as traditional systems, the requirements for thermal stability are further improved. At the same time, small and medium-sized satellite platforms reducing the thermal control resources further increases the difficulty of thermal control. Thermal control design requires adaptation to complex and harsh external heat flow environments, achieving high temperature stability and low thermal control power consumption, which poses challenges to thermal control design. Therefore, the high temperature stability thermal control design of ultra-low orbit remote sensors is of great significance and application prospects.Based on the overview and temperature index requirements of remote sensors, the focus and difficulties of thermal control design were analyzed. The key and difficult points in the thermal control design are specifically reflected in the following : 1) Because of the ultra-low orbit has low altitude, the external heat flow in shadow and sunshine areas and seasonal greatly changed; 2) When remote sensors imaging, it is necessary to maneuver, and the external heat flow will change with attitude; 3) The remote sensor has a flat design to reduce wind resistance and the optical lens is installed close to the inlet, which increases the angle coefficient between the inlet surface and the Earth, further widening the difference between high and low temperatures; 4) Higher requirements for full cycle temperature stability of ± 0.3 ℃ are proposed for thermal control which is a key factor in achieving the optical performance of the system; 5) Modern small satellites have limitations on power consumption and weight of thermal control resources, further increasing the difficulty of control.An external insulation combined with external precision control strategy was adopted to the system level thermal control design (Fig.4) achieves high temperature stability. The specific measures are as follows: 1) Camera’s door reduces the impact of external heat flow on the remote sensor, improve the temperature stability of the remote sensor, and save thermal control compensation power consumption. Table 2 show the temperature stability of each position of the remote sensor has been optimized and improved with camera door. 2) Reduce the thermal coupling between spacecraft and remote sensors and strengthen the insulation between key components. 3) The focal plane circuit box radiates heat dissipation to the cabin panel. 4) To reduce the impact of external heat flux, a high-precision temperature control radiation insulation structure was installed on the front support rod of secondary mirror and front mirror cylinder (Fig.5), which shields the influence of external heat flux while controlling the radiation temperature of key structures. 5) Add high thermal conductivity graphite to reduce temperature gradient, meanwhile reduce the number of thermal control temperature control circuits and power. 6) The regionalization and refined temperature control power density distribution design can be used for components with large temperature differences (Fig.6), to ensure the temperature stability of the controlled structure. Table 3 shows the temperature stability and gradient of front tube and secondary mirror bearing with refined heat shield improved, which beneficial for structural stability and improving imaging quality.To verify the correctness of the thermal control design of the main body of the remote sensing device, high temperature stability thermal control design measures were applied to the actual remote sensor. A thermal balance test was conducted in a large vacuum tank, and the thermal balance test results of the main components are shown in Fig.7-Fig.9. It was verified that high temperature stability thermal control design can ensure the main body temperature within the required temperature range under various extreme working conditions. After in orbit flight verification, Figure 10 shows that the thermal design effectively shields internal and external heat flow disturbances, the temperature meets the requirements. The temperature stability of key components throughout their entire life cycle can be better than ± 0.2 ℃.The characteristics of the thermal environment, structural form, and indicator requirements of ultra-low orbit remote sensors propose challenges for thermal control design which achieve high temperature stability control under multiple adverse conditions. The high temperature stability thermal control providing a good temperature environment for the main body through system level thermal control design used the concept of combining external insulation with internal precision control and measures like camera’s door, high-precision temperature control radiation insulation structure, graphite composite uniform temperature structure, and variable density refinement temperature control power. The ground test results and in orbit flight data proves the correctness and rationality of the high stability thermal control design.