Based on the cross section equilibrium equation and structural equilibrium equation, a numerical algorithm of aging analysis is proposed to calculate the aging effect of prestressed concrete structures by considering the shrinkage and creep of concrete and the relaxation of prestressed steel beam. This method can be used to predict the stress and deflection of prestressed concrete structures at any time from construction to operation to the whole design period. This theory has been verified by experiments and has been applied in practical bridge engineering.