Abstract: The onboard wideband reconnaissance receiver is faced with the problem of co-site interference of high-power radio transmitting signals in the same vehicle. One effective solution to this issue is interference reconstruction and cancellation. However, due to engineering errors, interference reconstruction signals and received signals cannot achieve perfect time synchronization, leading to a decline in the effectiveness of co-site interference cancellation. In this paper, we first establish the co-site interference cancellation system model for the Nyquist folded receiver and then consider the influence of non-ideal factors, such as the multipath effect of the interference propagation channel and time synchronization error. We provide closed expressions for the residual interference power and co-site interference cancellation ratio. Additionally, we theoretically analyze the influence of the time synchronization error of the co-site interference reconstruction signal on the performance of co-site interference suppression. The simulation results under different conditions validate the correctness of the theoretical analysis.