In the smart bar-beam structure with piezoelectric strain actuator active control function to vibration, the thickness effect of paste layer is considered and strain is assumed linear distribution along the thickness direction of each layer. The piezoelectric actuator point force model of Crawley and Luis is refined, a more general point force model is established to the smart beam with strain actuator. Point force model calculation formula is educed to smart beam with two-side symmetry paste actuator or one-side paste actuator. The computer simulation is done and the result reveals modified point model is right. The modified model is more common, as is important to design piezoelectric smart structure.