In the paper,taking 80 quadrats located in the parks of Zhengzhou as the research object,the carbon density of different community types,different community levels were analyzed. Meanwhile,the vegetation carbon storage of park ecosystem in Zhengzhou was estimated. The role was quantitatively evaluated in offsetting carbon dioxide emissions and mitigating the greenhouse effect. The results showed that the carbon density of different community types were obviously different in urban garden ecosystem. Taking parks ecosystem of Zhengzhou as an example,the evergreen coniferous forest had the highest average carbon density of 85.28 t·hm-2 and the deciduous broad-leaved forest had the smallest average carbon density of 50.69 t·hm-2. In 2018,the vegetation carbon storage of park green space in Zhengzhou was 294 684 t. It demonstrates that park green space in Zhengzhou had great potential in adding carbon sinks and reducing carbon emissions,and ecological benefits were remarkable.