运用ＭｏｎｔｅＣａｒｌｏ方法模拟了粒子在重力场中扩散控制的沉降过程，获得了不同粒径下的沉降图样，并用分维进行了分析。结果表明，随着粒子半径的增大，沉降图样堆积得越来越紧密，当粒径小于４３０ｎｍ时，分维数随粒径的增大迅速增大；大于４３０ｎｍ时，分维数增长缓慢，最后趋近于２。 The Monte Carlo method was used to simulate the process of particle diffusion control in the gravitational field. The settlement patterns of different particle sizes were obtained and analyzed by fractal dimension. The results show that with the increase of particle radius, the sedimentation patterns become more and more compact. When the particle size is less than 430 nm, the fractal dimension rapidly increases with the increase of particle size. When the particle size is larger than 430 nm, the fractal dimension increases slowly, Finally approaching 2.