To explore the relationship between the cathode pulse and signal-to-noise ratio (SNR), MCP voltage, imaging clarity, voltage between the MCP and anode, brightness stability, and the dynamic range of an image intensifier using different auto-gated power supplies, experiments were conducted using the same image intensifier tube with two types of auto-gated power supplies. The results show that the DC voltage of the cathode under low illumination can effectively improve the SNR of the image intensifier. Reducing the intermediate value of the MCP voltage can enhance the limited resolution and MTF of the image intensifier to a certain extent. A constant voltage between the MCP and anode can significantly improve the brightness stability of the image intensifier, and the maximum random fluctuation, steady-state drift, and maximum steady-state deviation under saturated illumination are substantially improved. The maximum working illuminance of the image intensifier with both types of auto-gated power supplies exceeds 1×10⁴ lx, and the new auto-gated power supply can further expand the dynamic range of the image intensifier.