Abstract: With the increasing amount of data generated by scientific research such as remote sensing satellite imaging and deep space exploration, conventional microwave communications are unable to meet the current transmission needs of high-speed and large-capacity satellite-to-ground communications due to limitations in bandwidth and related technologies. Laser communication technology breaks through the bandwidth limitations and becomes an important means of satellite-to-ground communications, especially suitable for the transmission of massive space science data. The system composition and experimental results of satellite-to-ground laser communications at home and abroad systematically are sorted out, including communication wavelength, communication rate, modulation method, wavefront correction technology. The key technologies for achieving stable and reliable communications, such as precise pointing, rapid acquisition, high-precision tracking, and onboard laser technology are introduced in detail. Given the impact of atmospheric turbulence on laser channels, effective suppression methods such as adaptive optics are analyzed. The development status of laser communication technology based on new structured light fields including vortex beam, vector beam, and optical pin beam is summarized. Finally, combined with the demand of space science for data transmission, the research progress of satellite-to-ground laser communications is summarized and future development direction is prospected, emphasizing its important application potential in space science and deep space exploration.