This paper analyzes the shortcomings of the traditional terminal and meter legality authentication methods, and proposes a new terminal and meter legality authentication method. This method calculates the internal authentication command of the power generation meter through the terminal, saves the communication process between the primary station and the electric meter, fully exerts the intermediate role of the terminal, improves the authentication efficiency, and improves the execution rate of the task. At the same time, the terminal supports the authentication method of the meter dispersion factor. Whenever the authentication is performed, the terminal key calculates the key of the meter according to the meter dispersion factor, thereby ensuring that each meter key required by the power information collection system is different.