The measurement of aircraft LRCS is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering from aircraft. A brief introduction of the measuring theory of the laser scattering from the target is presented in this paper. By analyzing the measuring condition in outfield test, the laser systems and test steps are designed for full size aircraft LRCS and verified by the experiment in laboratory. The processing data error 7% below is obtained of the laser radar cross section by using Gaussian compensation and elimination of sky background for original test data. The of measurement and analysis proves that the proposed method is effective and correct to get laser radar cross section data in outfield test.