The performance of transmit diversity(TD)assisted amplify-and-forward(AF)relay system with partial relay selection,which experiences mixed Rayleigh and Rician fading channels,is investigated.We first investigate the closed-form expression of the cumulative distribution function for the end-to-end equivalent signal-to-noise ratio(SNR),and then the exact expressions of outage probability and average symbol error probability(SEP)are derived.The theoretical observations are verified by the Monte Carlo simulation results.