This paper introduces a method to visualize the three－dimensional “electron cloud”of hydrogen atom by Monte Carlosimulation． According to the wave function of the electron in hydrogen atom，the visualization of three－dimensional electron cloud of hydrogen atom with different energy levels is realized by using Mathematica software and Monte Carlo simulation method，which makes people have a more intuitive understanding of the behav-ior of the electron in hydrogenatom． At the same time，this paper also gives a universal algorithm based on Monte Carlo method to study the electron cloud image of the general atomic system，including the perturbation system， which can be used for the further development of the visualization resources for the courses of quantum mechanics．