The health of urban community residents is an issue of growing concern due to ecological degredation, increasingly extreme changes in weather, the growing prevalence of economic downturns, and chronic population structure imbalances (e.g., rising elderly and unmarried populations, low birth rates, and rising immigrant populations) around the globe. Although the theory of ecology is commonly used by domestic and international researchers to explore health promotion issues in modern society, it has not been applied in assessing the problems of community health in Taiwan or elsewhere. This paper focused on one community in Taipei City's Xinyi District to investigate the feasibility of applying the ecological system theory to urban community health assessments in Taiwan and analyzed the influence of external environments on residents' health. Researchers used observation, in-depth interviews, a questionnaire survey and literature review to frame research and collect data. Community health assessment results show one of the main health problems in the target community resulted from inadequate resident abilities and actions related to health promotion. Some residents also maintained only distant interpersonal relationships with people in their immediate neighborhood. Findings suggest the need for implementing concrete schemes based on four ecological systems to resolve identified health problems that included inadequate community human resource integration and community consensus building.