The state of electron is described by wave function and the intensity distribution of multiple slits electron diffraction is derived by probability distribution of electron momentum.
The characteristic of light is the wave and particle.From the perspective of probability wave in quantum mechanics,the thesis describes the wave function of microcosmic particle and derives the distributive law of light intensity of the single slit and multiple-slit fraunhofer diffraction by means of the probability wave.The result accords with that obtained through the Huygens-Fresnel Principle.This method could help students to understand the wave function concept and the statistical meaning of wave function in quantum mechanics and understand the essence of light.