As an existing single laser warning system can only achieve a one-dimensional azimuth and wavelength information of the incoming laser light. A new method of single-laser warning system was proposed which can simultaneously measure two-dimensional azimuth and the wavelength information of the incoming laser light. The optical system consists of shade, grating, lens group and CCD array. Two-dimensional azimuth and wavelength information of the incoming laser light was measured by measuring the position of the zero-order and first-order diffraction. The basic principle was introduced, the equations of two-dimensional azimuth and wavelength measurement formula was derived. Depending on the project requirements, optical component parameters were deduced. The feasibility was verified through experiment. The experimental results show that the laser waring device can realize measurements of the incoming laser light, azimuth resolution no more than 1°, x direction field of view of 30°, y direction field of view of 15°.