Abstract: Information may be eavesdropped by eavesdropping users in the process of wireless communication which relies on open free space. To solve the information disclosure problem of multi-user downlink, a secure transmission scheme which is optimized by beam forming(BF) technology on the basis of time reversal(TR) technology is proposed in this paper. This scheme takes the maximization of security capacity as the principle of multiuser communication, builds a multiple input single output(MISO) wiretap channel model. On one hand, the base station uses beam forming technology to make the signals enhanced in the specified direction, and transmit the demand signals to the desired users. On the other hand, the signals of the base station need to pass through the time reversal cavities before being transmitted because of the environment adaptive technique-time reversal, and spatial and temporal focusing characteristics of time reversal technology make the energy focused on the legal receiver to make the performance of security better. The theoretical analysis and simulation results show that the proposed scheme has a higher security capacity and a lower bit error probability.