This study reviews the sustainable urban design concept and identifies critical factors for enhancing social sustainability of urban renewal projects. Through a questionnaire survey carried out in Hong Kong, the opinions of architects, planners, property development managers, and local citizens were sought and evaluated. The results derived from factor analysis indicated that certain design features should be incorporated for achieving social sustainability. "Satisfaction of Welfare Requirements", "Conservation of Resources & the Surroundings", "Creation of Harmonious Living Environment", "Provisions Facilitating Daily Life Operations", "Form of Development" and "Availability of Open Spaces" were believed to be the significant underlying factors for enhancing social sustainability of local urban renewal projects.