In order to study the near-field target characteristic of the laser fuse, an algorithm based on the relationship of bidirectional reflectance distribution function and laser radar cross section per unit area is proposed to calculate the echo power of laser fuse in the near-field. The main research work in this paper involves the followings (1)Based on the theory of beam division, a mathematical description of the angular distribution of the detonator laser beam is given to depicted the mathematical model of Gaussian beam. (2)By using the scattering characteristics of rough surface as well as the geometry mesh model of the target, the relation formula between received power and transmitted power of remote system for a facet is derived. (3)Establishing the missile-target encounter model though the conversion from different coordinate systems. Then calculate the echo power of laser fuse by integrating those of the geometrical elements which are illuminated by laser beam during missile target encounter. Consequently, the received power in each channels of the laser fuse can be calculated. In addition, the proposed theoretical model in this paper is calibrated by actually-measured data. And the emulation results are with a good agreement with measured results. Based on the theoretical analysis methods proposed in former chapters, we have developed a program to compute the echo power. Finally , we consider a simplified missile model, and compute its echo power under different angle and different material as well as different miss distance and different target miss in azimuth. The results show that scattering peaks correspond to the points of the wings of the missile. In addition, the results change obviously when using different material .For instance, the results with aluminum material are almost 10 times than that of white paint when ignoring the influence of atmospheric attenuation. At the same time, the results are different under the different miss distance as well as target miss in azimuth. Numerical results prove the proposed method high efficiency and preciseness. It would be especially valuable in engineering application.