Abstract: As a typical coal resource-based city, Huainan’s ecological security research is of great significance to reveal the evolution of man-land relationship and promote the transformation and development of mining cities. Based on the “pressure−carrying capacity−maintenance force” model, an ecological security evaluation index system was constructed. The comprehensive index method was used to evaluate the evolutionary characteristics of ecological security from 2011 to 2024. The grey markov model was used to predict the development trend from 2025 to 2030, and the obstacle degree model was used to diagnose the key constraints. The results show that during the study period, the comprehensive index showed a trend of “fluctuating rise-high drop-stabilizing adjustment”, rising from 0.311 in 2011 to a peak of 0.670 in 2020 and then falling back to 0.506 in 2024, and the safety level rose from level II to level IV and then moved back to level III. The contribution of subsystems is significantly different. The maintenance force is the dominant driving force for the improvement of ecological security, but the volatility is strong. The carrying capacity subsystem continues to be sluggish, which has become a deep-seated bottleneck restricting ecological security. The grey Markov model has a high prediction accuracy (MAPE = 4.278%). The prediction shows that the comprehensive index will rise steadily to 0.785 from 2025 to 2030, and will enter Level V (Safe) range from 2029. The total area of afforestation, the per capita disposable income ratio of urban and rural areas, the general industrial solid waste disposal rate, the natural population growth rate, and the per capita park green space area are the five major obstacle factors. In the future, Huainan City needs to focus on breaking the bottleneck of carrying capacity while consolidating maintenance, and provide scientific reference for the improvement of ecological security in resource-based cities.