Existing research on post-disaster economic impact focuses on direct economic loss and casualty, but ignores the indirect loss and dynamic impact. The paper analyzes the economic impact of wenchuan earthquake on Sichuan province’s GDP from both theoretical model and empirical analysis. Firstly, Solow model is used to describe different possible development after natural disaster; then C-D production function is used to test our theoretical models. We found that Sichuan has experienced an increasing speed due to post-disaster reconstruction compared with the counterfactual situation.