Abstract: An artificial noise-assisted beamforming method is proposed to ensure communication security and reduce the energy consumption of the full-duplex joint radar-communication system. Considering that the location of the eavesdropper is unknown, under the constraints of the secure communication requirement and the received signal-to-noise ratio from the target, the transmitted power is minimized through optimizing the transmit beamforming, receive beamforming and the added artificial noise. This optimization problem is analyzed by semidefinite relaxation and successive convex approximation, then a closed-form solution for the receive beamforming vectors of the radar and uplink communication are derived. And then, an iterative algorithm is proposed to obtain the optimal transmit beamforming matrix and artificial noise covariance matrix. Compared to the conventional half-duplex system, simulation results show that the system achieves full-duplex secure communication with a limited increased power consumption. Besides, compared to the commonly used block coordinate descent method, the proposed algorithm achieves lower power consumption.