Abstract: In this paper, the three-dimensional structure of a lead glass MCP was established under CST Particle Studio environment. The Finite Integration Method and the Monte Carlo Method were combined to simulate the multiplication process of secondary electron both under DC and Gaussian bias voltages. The dynamic distribution curves of charge density of secondary electron cloud along the axis of microchannel were obtained. The results show that the distribution of charge density of secondary electron cloud obeys Gaussian distribution. Under DC bias voltage, the density of secondary electron cloud is gradually increasing during the drift process, when the electron cloud drift to the position near the output electrode, the charge density reaches the maximum. Under Gaussian bias voltage, the pulse width has a decisive effect on the multiplication process of secondary electrons, when the pulse width is wider than the average transit time of secondary electrons, the multiplication process is similar to that under DC bias voltage.