This study focuses on the reliability assessment of buildings subjected to moderate earthquake loadings. The safety of the buildings is expressed with criteria of both global level and member level summarized from the deformation-based design theories in the overseas codes. The inter-story drift ratio is chosen as the key criteria. An allowable inter-story drift ratio of repairable level is proposed for seismic design, and a numerical example is examined. The results indicate that the allowable inter-story drift can effectively control the damage level under moderate earthquake.