A disasterresistance design method for bridge based on risk is developed by taking account the hazard model and the multilevel performance of bridge. Considering quantitative performance objects, fragility curves of every performance level are obtained through fragility analysis. The failure risk is determined by considering the failure probability, which is calculated by convolving the fragility curve with the hazard model and the damage ratio of every performance level. A tower of cablestayed bridge in seismic district is provided to illustrate the method.