Abstract: This paper presents a beamforming scheme to enhance security capacity of the hybrid satellite-terrestrial network.In this network, a satellite communication network termed as the primary network under the intercept of an eavesdropper that shares spectrum with a terrestrial network termed as the secondary network. First, we aim to minimize the transmit power of terrestrial base station, while the security capacity of the primary user and the communication capacity of the secondary user are satisfied.Then,we propose reformulation technique and semidefinite relaxation (SDR) to convert the optimiza- tion problem into the convex optimization problem can be solved by standard numerical packages, and use semidefinite program(SDP) techniques to calculate the beamforming vectors of terrestrial base station. Finally, simulation results are provided to verify the availability and superiority of the beamforming algorithm.