The spatial environment is the carrier of urban crime. Improper spatial environment provides conditions and opportunities for urban crime, which is the main factor that triggers residents’ fear of victimization. With the aid of the “CPTED” and the “vulnerable to crime” theories, the author proposes that the spatial position, the spatial morphology and the spatial atmosphere are three physical properties of buildings’ outside environment that affect residents’ fear of victimization, after teasing out the environmental characters that influence residents’ fear of victimization, such as accessibility, visibility, identifiability, territoriality, positivity and imagery, etc. The author puts forwards some defense safety design strategies on weakening residents’ fear of victimization for a typical semi-gated residential community in Changchun.