Abstract: The comparisons show that there are significant differences between the existing research works in aspects of the estimation on the average overtopping discharge of breaking wave on vertical wall and the effect of the impact factors, that to make a reliable choice among the works for engineering application, checks based on the independent experiment become necessary. To this end, systematic checks on the results estimated by the representative works were carried out based on physical model tests of random wave, and the reasons which make the difference between the works were analyzed combined with the investigation to the regulation of the factor's effect. The experiment results that the treatment on the main impact factors, such as the period and the bottom slope ratio, is highly responsible for the marked difference between the works; EurOtop generally makes the significant overestimation, while Goda (2009) is most consistent with the conclusions of current experiment with regard to both the treatment of the impact factors and the results of estimation.