Ocean Lidar has the technical characteristics of strong water penetration, high vertical resolution and all-day observation, so it has great application potential in satellite ocean profile measurement. But the accurate measurement of ocean Lidar is inseparable from the accurate calibration of system constant. To meet this requirement, a novel calibration method for ocean lidar system constant based on satellite-borne passive remote sensing is proposed. This method is based on the combined model of ocean active and passive optical remote sensing. By using the remote sensing reflectivity data obtained by satellite-borne passive remote sensing technology, real-time and efficient calibration of ocean LiDAR system constants can be realized on a global scale. Based on the self-developed airborne ocean Lidar and in-orbit Aqua-MODIS data, the proposed calibration method is validated by flight tests in the Beibu Gulf of Guangxi. The results show that the method is accurate and effective. After the calibration of LiDAR system constant, the root mean square of mean relative difference between the measured value and the theoretical value is 13.7%.