As urbanization rapidly progresses, the ecological resilience and health of urban parks and green spaces face significant threats, underscoring the crucial need for effective ecological quality assessments. This study developed a comprehensive evaluation system, uniquely designed with sixteen indicators across four dimensions – community composition, structure, succession, and disturbance – to systematically assess the near-naturalness of 87 urban park plant communities in central Hefei and to explore the influencing factors. Employing comprehensive index and random forest algorithms, we find the near-naturalness index ranging from 0.135 to 0.752, categorizing only 18.39% of samples as ‘nearnatural’ or ‘semi-natural,’ while a majority, 81.61%, fell into ‘far-natural’ or ‘artificial’ categories. Ideal near-natural conditions emerged in settings with 5 to 10 dead plants, litter cover of 10 to 30%, 10 to 15 species, and mild natural disturbances. Our findings indicate that the overall near-naturalness in Hefei’s urban green spaces is moderate to low, suggesting a need for focused enhancements in community succession and structural adjustments. This research establishes a novel framework for advancing urban green space ecological planning and sustainable development, providing fresh insights and a robust scientific basis for enhancing the ecological quality of urban parks and green spaces.