Abstract: The relationship between atmospheric column-averaged CO2 concentration measurement errors and operating wavelengths of space-borne integrated path differential absorption (IPDA) lidar was studied. The column-averaged CO2 concentration measurement principle was presented, and the system random error, temperature uncertainty error, frequency drift error and H2O interference error as a function of the operating wavelengths of lidar were analyzed. The operating wavelengths were optimized to minimize the total concentration measurement error. For optimal IPDA lidar on-line and off-line wave number of 6 361.225 0 cm-1 and 6360.99cm-1, the total column-averaged CO2 concentration measurement error was calculated to be 0.58710-6 with 1K temperature error and 0.6MHz frequency drift error, which meets the requirement of the column- averaged CO2 concentration measurement with 110-6 accuracy. The optimized wavelengths are applicable for retrieval of column-averaged CO2 concentration with high precision for space-bore IPDA system.