We investigate the validity of a method for estimating the critical slip-weakening distance (Dc), which was proposed by Mikumo and Yagi <2003>, for a dynamic rupture model of a recent earthquake. Assuming a uniform distribution of Dc on the fault, we simulated spontaneous dynamic rupture process and generated the synthetic waveforms that would be observed at actual recording stations. Then, we carried out kinematic inversion of the synthetic waveforms and obtained the slip-rate time functions on each subfault. We estimate Dc from these functions and discuss whether the assumed Dc could be recovered correctly. We also investigated the rupture propagation effect over each subfault with a finite dimension and the effects from the waveform inversion and band-pass filtering processes on the estimate of Dc. We found that the propagation effect could cause an apparent correlation between the recovered Dc'-values and the final slip.