【Objective】The mineralization process of soil organic carbon (SOC) and its components is complex. For example, particulate organic matter (POM) and mineral-associated organic matter (MAOM) are two components with different physicochemical properties and turnover rates. However, few studies have paid attention to the differences in the response of these different components to climatic factors. Thus, this study aimed to investigate the differences in the mineralization of POM and MAOM under different temperatures and moisture conditions and provide a basis for the estimation and prediction of CO2 emission fluxes in the context of global climate change. 【Method】The soil of Xilingol grassland in Inner Mongolia was collected to obtain POM and MAOM using a physical grading method and controlling the same mass of each fraction. Bulk soil was incubated under optimum conditions for 180 days, and POM and MAOM were incubated at different temperature and moisture conditions for 60 days to investigate the differences in mineralization of the two fractions and their response to temperature and moisture. 【Result】After 180 days of incubation experiments under optimal conditions, the cumulative CO2 emission from the grassland soil reached 2688 mg kg-1. MAOC in the grassland soil was relatively large, which accounted for 60% to 75% of TOC. Under different temperature conditions, the mineralization rates of both POM and MAOM increased with increasing temperature, while the two fractions responded differently to soil moisture content. There was a positive but insignificant correlation between the CO2 emission rate of MAOM and soil moisture, while there was no significant correlation between the CO2 emission rate of POM and soil moisture. It was also found that MAOM was much larger than POM in terms of cumulative CO2 emissions per unit of soil mass, while POM was much larger than MAOM in terms of cumulative CO2 emissions per unit of organic carbon. 【Conclusion】The mineralization of grassland soils MAOM and POM showed significant differences in response to temperature and moisture, suggesting that the mechanisms controlling the mineralization of these two carbon pools are different. The cumulative CO2 emission per unit of organic carbon in POM was much larger than that in MAOM, suggesting that the carbon in POM is more easily mineralized under the same conditions. Thus, distinguishing between POM and MAOM helps to better understand SOC turnover and provides a scientific basis for improving the SOC mineralization model.