With the increasing prominence of health issues at the national, social, and individual levels, the impact mechanism of spatial factors on health has become a focus of interdisciplinary research. Exploring the deep connection between urban density, green space exposure, and health is not only related to the improvement of individual physical and mental health, social health, but also the key to integrating and coordinating spatial factors. This study aims to explore the relationship between urban density, green space exposure, and health, and to explore the significance of these factors in the process of urban modernization. It is summarized as follows: (1) The development of green space exposure, quantitative assessment methods, and the research history, key research results, and emergent hotspots of urban density are summarized; (2) The interaction relationship between different research stages of urban density and health, and the interaction mechanism between green space exposure and health are systematically sorted out from both dynamic and static perspectives; (3) The active and passive relationship, mechanism, and future development direction of green space exposure in high-density urban environments, revealing the "competing relationship" between urban green spaces. This study emphasizes the importance of the holistic nature of green space in high-density urban planning and spatial governance, which can contribute to the overall well-being of the residents and the sustainable development of the society, hoping to provide a scientific basis for the construction of a more livable and healthy urban environment.