Parametric methods are the important techniques for the implementation of Radio Frequency Interference (RFI) suppression in Ultra-WideBand Synthetic Aperture Radar (UWB-SAR). In order to evaluate the practical performance of RFI suppression algorithms, several primary algorithms are compared by the interference suppression capability and pulse compression performance. The results with real data from our experimental UWB-SAR show that parametric algorithms can greatly improve the signal-to-interference ratio. Furthermore, the algorithms based on sinusoidal model are a little better than those based on AR model.