In order to evaluate and analyze the detection performance of lidar for optical properties in global ocean, the detection depth of spaceborne oceanographic lidar operating in blue-green spectral region was estimated and analyzed. This research was based on lidar equation and given lidar parameters. MODIS Level 3 annual averaged global water absorption coefficient a(λ) and backscatter coefficient bb(λ) were used as reference values for optical properties of sea water. The results show the distribution of detection depth depends on both detection wavelength and water optical properties. In clear open ocean, the best detection wavelength is near 460 nm and the maximum detection depths are approximated 110 m and 120 m in daytime and nighttime, respectively. In turbid coastal water, the best detection wavelength is mostly longer than 500 nm and the maximum detection depths can only reach 20 m or even shallower. The spaceborne oceanographic lidar achieves best global detection performance when the detection wavelength is between 470 nm and 480 nm.