The degradation of the eco-environment has been a challenge for sustainability in resource-based cities around the world. Although much attention has been drawn to this issue, few insights have been acquired regarding the spatial differentiation and mechanism of the factors influencing habitat quality in resource-based cities from the perspective of the interactions of natural and human factors. Using Tangshan City as a case study, this paper evaluates habitat quality by integrating Ecosystem Service Value Assessment and the InVEST-HQ model, identifies the spatial distribution of Tangshan's habitat quality with spatial auto-correlation, and explores the influencing factors and their mechanism of influence on the spatial differentiation with the geographical detector model and Space production theory. The results show that: (1) The total value of the habitat quality in Tangshan City in 2019 was 3.45×10¹⁰ yuan, and the habitat quality value was 24435.05 yuan ha^–1. The habitat quality value presents a clustered distribution pattern of “hot in the north and the south, cold from the center to the west”. (2) On the county scale, Qianxi County had the best habitat quality and Lubei District had the worst habitat quality; Shangying Township had the highest average habitat quality and Kaiping Street had the lowest average habitat quality in the township unit. (3) The results of geographical detectors show that natural environmental conditions are the important basic factors affecting the spatial differentiation of habitat quality in Tangshan City, while urbanization and industrialization factors are the most important external forces driving the spatial differentiation of habitat quality. The contributions of average elevation, average slope, raw material industrial density, and population density to the spatial differentiation of habitat quality are all above 0.40. The interactions of any two factors on habitat quality are enhanced. Areas with concentrated populations, rich industrial resources, and convenient transportation become low-value habitat quality areas; while areas with beautiful landscape patterns, abundant precipitation, and a comfortable climate become high-value habitat quality areas. Space production theory can be used to explain the mechanism of the formation of the spatial differentiation of habitat quality.