The array of grating units consists of a large number of units, and the size and shape of each unit need to be precisely controlled to ensure the shaping effect of the beam. However, in the process of optical communication, the change of light intensity distribution will cause the response of each unit in the grating array to be inconsistent, which will cause the difference of the optical signal received by each unit, and then affect the shaping effect of the beam. Therefore, a beam shaping method for optical communication grating array considering light intensity distribution is proposed. Taking the most commonly used array waveguide grating in optical communication grating arrays as an example, by analyzing the core width, core refractive index, cladding refractive index, waveguide period width and other parameters of the array waveguide structure, combined with the influence of beam wavelength and refractive index on the propagation constant in the waveguide, the normalized eigenequations of the array waveguide are obtained. The results are combined with the uniform Lorentz function to obtain the intensity distribution of the incident and outgoing light, By calculating the mapping functions of the incident and outgoing light of the optical communication grating array beams, the optical parameters can be adjusted using the functions to achieve beam shaping of the optical communication grating array beams. The experimental results show that this method has good shaping effect on the optical communication grating array beam, high energy utilization efficiency of the shaping beam, and small beam non-uniformity.