Abstract: The paper analyzes the principle of AOA ranging algorithm, designs the overall framework of the precise positioning system for the mine personnel, and proposes a precise positioning system of mine personnel based on AT86RF233 phase difference ranging. The card reader uses two directional antennas to receive wireless signals, and realizes direction recognition based on the received signal strength differences of the two antennas. The collision of wireless signals is solved by time division multiplexing and dual channels. The experimental results show that the positioning accuracy of the system is less than 1.0 meters and the effective coverage is up to 200 m, which meets the high-precision positioning requirements of the mine and verifies the feasibility of the scheme.