In order to encrypt and decrypt exactly the transformed information, the synchronization of hyper chaotic Lorenz system was proposed to realize secure communications. Based on the linear system stability theory, an output feedback controller was designed to get the output feedback controlling synchronization of hyper chaotic Lorenz system. Also, the synchronized system was used in chaos masking approach. Simulation results show that the synchronization of hyper chaotic Lorenz system was realized fast, and the useful signal can be recovered from the receiver effectively.