Coal is the primary source of energy in China. Generally, it is believed that coal resource-based cities, where the coal industry serves as the dominant sector, should not face energy security issues. However, due to the characteristics of coal energy resources and the typical lifecycle patterns of coal resource-based cities, these cities not only confront significant challenges in terms of energy structure security but also increasingly manifest severe ecological security issues resulting from coal resource exploitation and utilization. To address these issues, this paper adopts a systematic approach, focusing on typical coal resource cities in the growth period. Using the pressure-state-response model, this paper constructs a multilevel heterogeneity index system for evaluating the energy security of coal resource cities, and makes an objective assessment. On this basis, this paper diagnoses the energy security of coal resource cities. Drawing on the theory of sustainable development, this paper proposes a path to improve the energy structure and ensure the energy security of Chinese coal resource cities, aiming to promote the green development of regional socio-economy.