基于几何光学的基本原理 ,建立了变截面波导刀体中光传输的约束方程 ,利用Monte Carlo法模拟了激光手术刀出射光束的空间分布 ,计算结果与实验结果基本吻合 ;讨论了不同设计参数对激光手术刀出射光束空间分布的影响 ;为该类刀头的设计提供了理论依据及直观有效的数值模拟方法 Based on the basic principle of geometrical optics, the constrained equation of light transmission in variable cross-section waveguide cutter body was established. The Monte Carlo method was used to simulate the spatial distribution of laser beam. The calculated results agree well with the experimental results. Laser scalpel beam distribution of the impact of the spatial distribution; for the design of this type of cutter provides a theoretical basis and intuitive and effective numerical simulation method