Soil organic carbon (SOC) mineralization is a significant process in soil carbon cycling in the terrestrial ecosystem, which is closely related to the soil nutrient release and global climate change. Function of urban soil as an ecosystem has degenerated due to severe human disturbances, which deeply influence the geochemical cycles, especially the carbon cycle, in urban eco-environments. In order to explore the variation in SOC mineralization and SOC sequestration potential under various land cover types, we collected soil samples from five typical land cover types, i.e., grass-covered, shrub-covered, street tree-planted, grass-planting brick, and impervious surface, in the Olympic Forestry Park in the summer of 2016. SOC mineralization and physico-chemical properties, such as pH, particle constitution, and nutrient content, of all soil samples were measured. After the experiment, we analyzed the variation in SOC mineralization under various land cover types and the relationship between SOC mineralization and soil physico-chemical properties. The results showed that the SOC mineralization of urban soil was higher at the early incubation period than that at the late incubation period; the same trend also favored the SOC mineralization in natural ecosystems. However, relatively significant differences in daily and cumulative SOC mineralization were observed among the five land cover types, especially in the early incubation period. Both daily and cumulative SOC mineralization under shrub-covered, street tree-planted and grass-planting brick types were higher than those under the other two land cover types, which was consistent with the variation in the SOC content under the five land cover types. SOC mineralization of all soil samples in this experiment followed the first-order kinetic equation. Simulation results showed that the SOC sequestration potential was relatively weaker under the impervious surface, grass-planting brick and street tree-planted types than under the grass-covered and shrub-covered types. In contrast with the variation in SOC mineralization, the variation in the SOC sequestration potential under the five land cover types was inconsistent with that in the SOC content, because SOC content may be deeply influenced by human disturbances and additional organic carbon input. With regard to the variation of SOC mineralization along layer depth, there was no significant difference among three layers (0-15, 15-30, and 30-45 cm) under the impervious surface type. However, under the other land cover types, especially under the grass-planting brick and street tree-planted types, the SOC mineralization of the top layer was greater than that of the lower layers as a whole. Correlation analysis suggested that the SOC content was the main constraint of SOC mineralization whereas other physico-chemical properties, including pH, nutrient content, and clay content, may indirectly influence SOC mineralization, by affecting the SOC content and microbial activity.