To determine a reasonable bivariate design flood synthesis, three typical bivariate return period standards including C-measure return period, joint return period, and co-occurrence return period were selected for the frequency analysis of flood peak based on Copula function. The maximum likelihood method, conditional most likely combination, and bivariate equivalent frequency combination were chosen as the representative calculation methods. The optimum design flood synthesis was then obtained from the results calculated by the different methods. The calculation method was applied to the Xin’an River Basin. The result shows that C-measure return period can be a standard in bivariate frequency analysis as it defines rational dangerous regions. It can also avoid the potential safety hazard of co-occurrence return period and is more economic than joint return period.