According to the results of a sloping seawall model test,we obtaine the fitting formula.Using the fitting formula,standard formula and empirical formula given by researchers,we calculate the secondary wave height produced by overtopping of the the sloping seawall under a different crest elevation,and compare the results with the model test,from which we know that the result by the fitting formula and test results are close most to each other;we also analyze the reason why the results from other fitting formulae are not consistent with the test result.The results may serve as reference for the secondary wave height calculation and model test of other slopping seawalls which allow the overtopping during the crest elevation design.