Soil nutrient improvement in karst ecosystem is very important for the sustainability of ecological restoration. Exploring the characteristics of leaf litter decomposition rate and nutrient release in the karst ecosystem is of great significance to select excellent tree species that improve soil nutrient availability. Leaf litter from four native tree species (i.e. Archidendron guangxiensis, Deutzianthus tonkinensis, Excentrodendron tonkinense, and Hainania trichosperma) in a north tropical karst seasonal rainforest was collected to conduct a 365-day field decomposition experiment. Then, the litter decomposition rate and the release of carbon (C) and nitrogen (N) were investigated, and their relationships with initial physicochemical traits (i.e. C content, N content, phosphorus (P) content, cellulose content, lignin content, tannin content, C/N, C/P, N/P, lignin/N, specific leaf area, and standard water-holding capacity) were also examined. The results showed that the order of leaf litter decomposition rate was H. trichosperma (k = 0.66) > E. tonkinense (k = 0.45) > D. tonkinensis (k = 0.42) > A. guangxiensis (k = 0.39), and their times required to decompose 95% were 4.51, 6.72, 7.17, and 7.68 years, respectively. Initial C content, specific leaf area, standard water-holding capacity, and tannin content were the important physicochemical traits affecting leaf litter decomposition in the north tropical karst forest. The order of leaf litter C release rate was H. trichosperma > D. tonkinensis > E. tonkinense > A. guangxiensis. The constant k of C release rate ranged from 0.74 to 1.17, which was higher than the global average of 0.69. The order of leaf litter N release rate was H. trichosperma > A. guangxiensis > D. tonkinensis > E. tonkinense. The C and N release of litter were decoupled. The C release rate was controlled by both the initial chemical (cellulose, N/P, N, and C) and physical traits (specific leaf area, standard water-holding capacity) of leaf litter, while the N release rate was only controlled by the initial chemical traits (C/N, cellulose/N, N, lignin, and N/P). Taken together, H. trichosperma leaf litter has the fastest decomposition rate and the release rate of C and N, while the N-fixing tree species A. guangxiensis leaf litter has the highest N content and high N release rate. As the dominant native tree species in the karst area, H. trichosperma and A. guangxiensis have high litter fall production and high decomposition rate or N release rate, which can be used as potential tree species for improving soil nutrients in rocky desertification.