Abstract: Aiming at the space laser communication system requirement of miniaturization, this paper proposes a scheme of using the four-quadrant detector to complete the acquisition and tracking. By analyzing the position distribution of the spots on the four-quadrant detector (4QD), the acquisition models are derived for the three kinds of spots distribution. Through the calculation of the position of the spots and the accurate calibration of the tracking mechanism, the high precision tracking is realized. Then besed on the laserteco and system test platform the capture and tracking scheme and detection performance of the 4QD are experimentally verified. The test results show that under the laboratory dynamic conditions, using 4QD as the capture and tracking detector, the capture probability is up to 100%, and tracking accuracy is better than 3μrad, which verifies the feasibility of the scheme and lays a foundation for the miniaturization design of the laser terminal.