Many historic buildings of Zhejiang province are located in the center of the city, and most of them are dilapidated. Therefore, they were the first eliminated objects in urban renewal and construction during the urbanization of Zhejiang province. We analyzed development and deduction characteristics of historic buildings to discuss techniques and methods for historic building preservation, and took Ningbo Qing’an Hall maintenance projection as an example to research on the preservation and restoration of historic district.