In this article the transmission characteristics of laser in multilayer coatings are analyzed. The work consists of two parts: First, electric field intensity distribution in a coating designed of A/H (LH)N/G structure is simulated numerically. Second, electric field intensity distribution in multilayer coatings designed of different N or optical thickness are further analyzed. The results show that：In the coating designed of A/H (LH) N/G structure, the maximum values of intensity decrease layer-by-layer at a definite ratio. The extreme values of intensity occur at the interfaces between layers. In the multilayer coatings of N=5, 10, 15, the extreme values of intensity occur at the interfaces changelessly. As N increases, the reflectance of multilayer coating approaches to 100%. In the multilayer coating of thicker optical thickness, the extreme values of intensity occur at the inner of each layer. As optical thickness increases, the reflectance decreases.