A system for acquisition, pointing and tracking in space optical communication was designed in this paper. AT89S52 processor was used for controlling the movement of the motors, which acceptted data from upper processor via serial port. And the raster-spiral scanning carried out by two-dimensional scanning mirrors was adopted to realize the acquisition of the laser beam. The tracking of the target was achieved by the image processing algorithm based on open source computer vision library (OpenCV). The equipment possessed high concentration degree, high real-time index and low power consumption, with an overall dimension of 248mm×245mm×85mm and a total power consumption of 24.55W which was easy to operate. The results showed that the system could achieve the scanning range of 120°within 50s and also met the coarse tracking's requirements.