The beam propagation characteristics of a one-dimensional coherent array semiconductor laser in the far field are researched. By establishing a mathematical physical model, the laser beam intensity distribution in the far field of a one-dimensional coherent array laser is calculated and simulated. The influence of array length, wavelength and duty ratio on the spot width in the fast and slow axis of the coherent array at different distances is analyzed. Research results show that the optical field of one-dimensional coherent semiconductor laser array is affected by the coherent action of the sub-source in the slow axis direction. The spot width in the slow axis direction differs by about 4 orders of magnitude compared with that in the fast axis direction in the far field. Thus, the laser spot is distributed in the shape of “blade”.