The urbanization of China is changing from incremental growth to urban intensification, and urban compactness is a significant attribute for measuring the intensified degree of regional space and societal frameworks. We carefully outline the inadequacies of compactness measuring methodologies and associated research, and argue that compact cities and metro systems contribute to urban sustainable development in tandem. Thereby, this paper investigated 27 strategic region of metro stations on Chengdu Metro Line 1 and proposed a novel urban compactness model in three-dimensions. The result demonstrates that the old urban area before the development of the metro system and the new town thereafter have extreme compactness outcomes, resulting in significant contrasts in morphology and intensification indices. This study investigates the correlation and interaction processes among compactness, morphology, and intensive multiple variables in order to give theoretical and practical support for the intensification design of these two regions in Chengdu.