In order to improve mechanical strength of corrugated paper, reduce its basic weight, and enhance its mechanical property, kelp/ PVA combination sizing method was studied. Kelp/ PVA combination sizing agent was prepared and corrugated paper was taken as research object to determine the best parameters. The result showed that the best parameters were: kelp density 10 g / L, PVA concentration 100 g / L, kelp and PVA volume ratio 3 : 1, sizing weight 5. 0 g / m2, and double sizing along paper fiber direction. It was found that while the best parameters were chosen, the tensile strength increased by 5. 0% , elongation increased by 5. 4% ; surface frictional coefficient was obviously reduced and static friction coefficient reduced by 20% . After thermal aging treatment, tensile strength of sizing corrugated core paper reduced by 1. 6% , less than 4. 6% of that compared paper.