To study the joint distribution of annual extreme wave height and annual extreme period of waves in the central Yellow Sea, five univariate distributions were fitted to the annual extreme wave height and annual extreme period based on SWAN hindcast wave data from 1999 to 2018 at three locations in the Yellow Sea, and the optimal marginal distributions of annual extreme wave height and annual extreme period at each location were obtained through the evaluation of the goodness of fit. The joint distribution function of annual extreme wave height and annual extreme period was established using the Copula function theory, and compared with the univariate distribution of wave height and period design values. The results show that there may be regional characteristics in the joint wave height and period distribution in the central Yellow Sea; the design values of wave height and period obtained from the joint wave height and period distribution are higher than the design values of univariate distribution at the same design frequency; under the same design frequency, the univariate return period is the largest, the conditional return period is the second and the joint return period is the smallest.