Facing the growing problem of carbon emission pollution, the scientific and reasonable division of environmental management power between governments is the premise and institutional foundation for realizing China's carbon emission reduction target in 2030. Although existing studies have focused on the relationship between Chinese decentralization and carbon emissions, most of them are based on fiscal decentralization indicators to depict China's environmental decentralization, lacking of systematic analysis and empirical test of institutional factors affecting carbon emissions from the perspective of environmental management. In this paper, we directly assess the environmental decentralization degree according to the allocation of environmental management personnel among different levels of government. By incorporating fiscal decentralization indicators, the provincial panel data and dynamic spatial econometric model are used to empirically test the impact of environmental decentralization on carbon emissions from spatial perspective. The study found that: (1) China's provincial carbon emissions have a significant positive spatial autocorrelation, showing a clear trend of high-high, low-low aggregation, and the carbon emissions of the previous period and the current have an obvious positive relationship. (2) At the national level, environmental decentralization, environmental administrative decentralization and environmental monitoring decentralization significantly reduce China's carbon emissions, while environmental supervision decentralization and fiscal decentralization significantly aggravate carbon emissions, which means that China's current environmental decentralization systems are generally conducive to carbon emission governance. The interaction between fiscal decentralization and environmental decentralization with its decomposition indicators significantly promotes carbon emissions, and its impact is related to the category of environmental decentralization, indicating that when local governments have greater environmental management power and fiscal autonomy, the combination of the two will push up carbon emissions. (3) The carbon emission effects of environmental decentralization in different regions are spatially heterogeneous. In the central region, environmental decentralization, environmental administrative decentralization and environmental supervision decentralization can promote carbon emissions apart from environmental monitoring decentralization. In the western region, the carbon emission suppression effect of environmental decentralization, environmental administrative decentralization and environmental monitoring decentralization is stronger than the eastern region, but the inhibitory effect of fiscal decentralization and environmental decentralization with its decomposition index interaction on carbon emissions in the eastern region is significantly better than the central and western regions. The above results provide policy ideas and theoretical support for the construction of the environmental management system with long-term carbon emission control in China in terms of regional differences and categories of environmental management power.