Abstract: Space science instruments use solar-guide mirror pointing and tracking systems based on four-quadrant photodetectors to achieve precise pointing control of the sun. To satisfy the requirements of high precision and stability, a four-quadrant photodetector screening method for space applications was proposed, and a screening system for the four-quadrant photodetector was developed. By comparing the dark current, responsivity, and quadrant responsivity uniformity of the four-quadrant detector before and after the screening test, the space-environment adaptability of the detector was analyzed according to the discriminant criteria. Additionally, detectors with early failures or large changes in performance can be eliminated. The results show that the developed screening system has high accuracy, and the equivalent input-current noise at the front end of the system is 0.58 fArms. After the screening test, the maximum absolute value of the dark current of each channel of the detector selected according to the evaluation standard was 6.08 pA. The maximum change in the response of each channel was 0.716%, and the maximum change in the response of each quadrant before and after the nonuniformity screening was 1.24%. Finally, the four-quadrant detector was applied to the solar guide mirror pointing and tracking system, and met the requirements of aerospace environmental conditions. The screening device and screening method can be employed to screen four-quadrant photodetectors for space applications, providing significance reference for the screening of other photoelectric devices.