Abstract: Reliability analysis considering damage effect of materials is studied for concrete structures. The damage bounding surface concept is introduced to develop the modified four parameter Hsieh-Ting-Chen model. Based on the modified model, a limited state function corresponding initial damage surface is constituted to study the safety of huge bulk concrete structures. Combining the response surface method and the finite element method to fit the limited state function, an approach that can be used to analyze reliability of complicated structures is established. As an example, a gravity dam is selected to study its reliability under static and dynamic loads with the approach. Satisfactory results are obtained.