A combination method between relative measurement and absolute measurement is presented,which obtain the distribution of optical intensity for a 1.4 kW pulsed TEA CO₂ laser in the distance of 335 m. Then the results of measurements are discussed and analyzed. The experimental results show that this approach is a good and precise and considers the influence of atmosphere which is the main factor. Flat top and fragmentation come forth in the distribution of optical intensity and furthermore appears one side lobe,which has very important reference value for evaluating the tactical effectiveness and optimization design of laser system.