Waveform parameter estimation of external illuminator is the basis of waveform synchronization and target detection in passive bistatic radar (PBR). Comparing with single-waveform situation, multi-waveform parameter estimation is much more difficult and complicated due to the uncertainty of transmission. To address this problem, an effective parameter estimation method is proposed. First, an adaptive direct-wave extraction method is used. Subsequently, based on the existing generalized Radon Fourier transform (GRFT), the effective estimation flowchart is given for pulse width, bandwidth and carrier frequency of each pulse. Finally, numerical experiments are provided to demonstrate the effectiveness of the proposed method.