Abstract: Particulate backscatter coefficient (b_bp) is the core parameter of ocean optics when applied to marine ecology and biogeochemistry. However, the current commonly used in-situ methods can not carry out large-scale detection in a short time, and passive ocean color remote sensing can not work under dark and cloudy conditions. In contrast, the active remote sensing method, spaceborne Light Detection and Ranging(lidar), can break through the above limitations, and has great advantages in ocean detection. Cloud Aerosol Lidar with Orthogonal Polarization(CALIOP), launched in 2006, became the first spaceborne lidar able to provide global seawater b_bp, particularly important for polar and diurnal observations. In this paper, the principle of the CALIOP system and three levels of its major data products were introduced in detail. Paper focused on combing the method of b_bp inversion with the depolarization ratio of the CALIOP 532 nm polarization channels and the subsequent improvement measures such like the deconvolution method correcting the transient response of the system. A corresponding algorithm was fully developed, which the detailed complete inversion process was summarized, and the current b_bp inversion results were presented. The works were intended to provide reference for data processing and application of the China space-borne oceanic lidar in the future.