Abstract: Differential absorption lidar is an effective methods for high-precision CO2 concentration measurements. In this paper, the major error sources of airborne differential absorption lidar CO2 measurement were studied, and CO2 concentration errors caused by them were analyzed. The airborne differential absorption lidar principle was introduced first, CO2 concentration errors from atmospheric temperature, pressure and water vapor uncertainties, laser frequency stability and the aircraft speed and attitude measurements uncertainties, as well as random error were analyzed. The results show that airborne differential absorption lidar measured CO2 column concentration error is about 0.71 ppm(1 ppm=10-6) for 380 ppm atmosphere CO2 concentration, which meets the 1 ppm accuracy requirement of CO2 concentration measurement.