The divergence angle of laser beam used in space laser communication is usually no more than 100μrad.Using laser beam with small divergence angle to achieve acquisition and tracking for space laser link has always been a difficult problem.In addition,the random nature of the atmosphere will affect the satellite-ground laser link,which increases the difficulty of the acquisition and stable tracking for the laser link.Thus,taking into account the above challenges for satellite-ground laser communication,an acquisition and tracking scheme of using both beacon beam and signal beam was designed for the Laser Communication Terminal (LCT) of Shijian 20 satellite.In-orbit test results indicated that under the condition of moderate atmospheric turbulence (atmospheric coherence length r0≈3cm),the process of acquisition and tracking for the satellite-ground laser link can be completed within Is after the initial pointing between the LCT and Optical Ground Station (OGS) is performed,and the tracking error was less than I μrad (3σ).In addition,the laser link can be re-established quickly once being interrupted by unsteady atmospheric turbulence,and can be maintained for a long time under moderate twurbulence conditions,which lays a foundation for future application of satellite-ground laser communication.