[Objective] The characteristics of litter decomposition in karst forest ecosystems were studied in order to provide scientific basis for prevention and control of rocky desertification and soil and water conservation in karst forest natrue reserve.[Methods] By using 1 mm mesh pore decomposition bag, the decomposition dynamics of different tree species of leaf litters(deciduous and evergreen leaf) in different slope position for 18 months were analyzed, including the dynamic change of litter loss rate and dry weight residue rate, decomposition rate and nutrient release characteristics of Maolan Karst Forest Natrue Reserve.[Results] The decomposition process of litter showed a "fast-slow-fast" cycle, and the decomposition rate in spring and summer was faster than that in autumn and winter. The decomposition rate of deciduous tree litter was faster than that of evergreen tree litters, and the decomposition rate of litters on different slopes was characterized by downhill > mid slope > uphill. This study used the Olson model to estimate the time of decomposition of 50% and 95% leaf litters. The time required for decomposing 50% and 95% of deciduous tree litter is 0.95~1.66 a and 4.13~7.19 a, respectively. The time required for decomposing 50% and 95% of evergreen tree litter is 1.14~1.69 a and 4.92~7.30 a, respectively. The difference between them is not significant. The decomposition rate of leaf litter in the Maolan karst forest was lower than that of the evergreen broad-leaved forest and evergreen-deciduous broad-leaved mixed forest in the eastern subtropical zone, but higher than that of the karst secondary forest and plantation in the same region. The release pattern of N element in deciduous and evergreen leaves is enrichment-release mode, and the C content varies significantly with the decomposition time. The overall trend of C content is reduced, so the C/N ratio is decreasing.[Conclusion] Due to the difference of initial nutrient content and leaf physical and chemical structure of different tree species, deciduous leaf had faster decomposition rate and nutrient release rate than evergreen leaf, which played an active role in promoting material circulation of karst forest ecosystem.