Currently, urban safety problem attracts much attention. The paper provides a research framework for building safer cities. The safer city has not only less crime and terrorism attack but also more resilience to all kinds of disaster. After clearing about factors that influence urban safety, authors try to build a value system. From the point of view of the urban safety, the paper reviews the existing physical planning and brings forward a urban spatial structure that attach importance to urban safety. The framework also includes the study on safer community and support systems such as law, policy and technology.