The far-field characteristics of the main lobe of two-dimensional coherent array laser beam are studied. The mathematical and physical models of coherent array laser beam propagation with square and regular hexagonal sub light sources are established. Through numerical simulation and analysis, it is concluded that the error of Gaussian function to describe the far-field central main lobe intensity distribution of coherent array laser beam is very small, and the propagation law of coherent array laser beam can be described according to the fundamental Gaussian beam propagation law of single aperture laser. On this basis, the energy ratio of the central main lobe in the far field is calculated. Calculation results show that the energy ratio of the central main lobe in the far field is hardly affected by the number of sub light sources. With the increasing of duty cycle, the energy proportion of central main valve increases gradually. When the aperture of coherent array laser is completely filled, the maximum energy proportion of the central main lobe of square laser beam is 79.1%, and the proportion of regular hexagonal arrangement is 83.2%.