In the past, using the modal incremental dynamic method to evaluate the seismic collapse capacity of public buildings did not accurately reflect the earthquake collapse resistance of public buildings, thus gaining poor economic benefits. In this study, a new and optimized evaluation method of determining the seismic collapse capacity of public buildings is proposed and used to analyze the overall performances of public buildings. Then, the relationship among the overall structure of public buildings, substructures, and components is summarized. The overall evaluation on the public building is fulfilled by evaluating the damage situation of components. Based on the seismic damage interval of public buildings, the optimized evaluation on seismic collapse capacity of public buildings are finished with the proposed method, and the damage indices of the seismic collapse capacity of public buildings are obtained. The experimental results indicate that the proposed method could exactly describe the seismic collapse capacity of public buildings, thus improving the economic benefits.