High-energy lasers are widely used in the fields of science, industry and military. Because of the influence of atmosphere on the transmission of a laser, the investigation of far-field beam quality of a high-power laser is always a problem. To obtain the optical intensity distribution of a 1.4 kW pulsed TEA CO₂ laser at the distance of 500 m, a relative measurement method combined with absolute measurement is proposed. The measurement data are discussed and analyzed. The experimental result shows that the maximum power density on the target is 1.65 W/cm2 and the divergence angle in the cross direction is up to 0.96 mrad. The result is valuable to the optimization design of laser systems.