In this paper, we investigate the performance of a dual-hop amplify-and-forward (AF) relay system with beamforming (BF), where the source and destination are both equipped with multi-antenna, which are correlated in space, while the relay has a single antenna corrupted by multiple co-channel interferences (CCIs). We first derive the closed-form expression for the outage probability (OP) of the output signal-to-interference-plus-noise ratio (SINR). Then, we present an approximate yet accurate expression for the average symbol error rate (ASER) of the AF relaying. Moreover, asymptotic expressions of OP and ASER at high signal-to-noise ratio (SNR) are also provided to reveal the diversity order and array gain of the considered relay system. Finally, computer simulations are given to validate the analytical results and demonstrate the effects of antenna correlation and CCI on the dual-hop AF relay network.