Abstract: For the broadband multi-antenna system, the clusters can be extracted from the channel information according to their different delays and azimuths, and used to generate the secret keys to improve the security performance. In this paper, the performance of the cluster properties-based secret key generation method is studied and evaluated by the average secret key rate and the outage secret key rate. Based on the theoretical analysis and the simulation verification, the influences of the number of the multipath components (MPCs) in a cluster, the azimuth spread and the signal-to-noise ratio (SNR) on the average and the outage secret key rates are presented. It is showed that the large number of the MPCs and the high SNR can improve the security performance. In the high SNR situation, the large azimuth spread also helps to improve the performance. But in the low SNR situation, the large azimuth spread decreases the performance.