The Paretian optimization of allocation of the resources in social insurance of supporting the old is carried into execution through insurance institution of supporting the old.From three perspectives (relationship between contribution rate and average substitution rate, insurance fund collection model, the method of calculating and providing pension), this paper analyses the Paretian optimization of allocation of the resources in social insurance of supporting the old.In addition, interest rate and income growth rate have important effects on balancing insurance fund and optimizing allocation of insurance resources.