The importance of regions in shaping sustainable economic growth trajectories has been the subject of extensive research in recent years. When sustainable growth has been investigated in developing countries, a particular focus has been on China's unsustainable development approach, which is characterized by high energy consumption and high pollution. Crucially, most of the research so far has focused on topics concerning ecological environment improvement. However, little is known regarding how the quality of human settlements environment can be accurately measured in terms of the concept of strong sustainability at the regional level. This study investigated human settlement environmental quality across 30 provinces in China from the perspective of strong sustainability and attempts to shed light on its spatial influence factors. Estimates are presented using a projection pursuit method. The results reveal that the quality of human settlement ecological environment declined over the period 2002-2014 with a significant geographical disparity in index performance. The results also suggest an observable spatial effect. The energy structure, energy intensity, and environmental control in a province not only have significantly positive effects on ecological quality of a province itself, but also bring spillover effects on its neighboring provinces. These three factors are also important in determining human settlement ecological quality in China.