Microchannel plates (MCP) are devices that achieve electronic multiplication in the low-light intensifier system. MCP have the advantages of high gain, small size and light weight, being widely used in modern low-light, infrared, and ultraviolet image detection fields. In this paper, the fatigue and damage of MCP caused by strong input current are studied. The fatigue and damage of MCP are mainly reflected by the change of gain and body resistance. Experiments show that the gain of the MCP decreases under the condition of strong electron flow (2nA), and the body resistance decreases sharply after being damaged.