To detect faint target stars of 22nd magnitude and above, an astronomical exploration project requires its space camera's readout noise to be less than 5e(-) with long-time working stability. Due to the limitation of satellite, the traditional CCD detector-based camera does not meet the requirements, including volume, weight, and power consumption. Thereby, a low-noise ultra-stable camera based on 9 K x 9 K large target surface CMOS is designed to meet the needs. For the first time, the low-noise ultra-stable camera based on CMOS detector will be applied to space astronomy projects, remote sensing imaging, resource survey, atmospheric and oceanic observation and other fields. In this paper, the design of the camera is introduced in detail, and the camera is tested for several rounds at -40 degrees C; it also undergoes further testing and data analysis. Tests proved super stability and that the readout noise is lower than 4.5e(-). Dark current, nonlinearity and PTC indicators meet the requirements of the astronomical exploration project.