The karst area of southwestern China covers 550,000 km², and includes 105,000 km² that are experiencing serious rocky desertification and human disturbance. Fortunately, national and provincial conservation and afforestation projects have been developed to mitigate karst rocky desertification. Ecological stoichiometry, which approaches questions by analyzing the balance of many major elements needed by organisms and determines how those elements affect and interact with processes, provides new perspectives for studying ecosystem processes in fields ranging from leaf physiology to ecosystem productivity. In terrestrial ecosystems, the close interaction between the C, N, and P cycles constrains most ecosystem processes; therefore, the N and P status, and the N:P stoichiometry of leaves has been studied intensively to try and determine how these factors limit plant growth. Exploring the stoichiometric properties of the primary elements (C, N, and P) in live fresh leaves and leaf litter is very important and could provide constructive information and guidance for ecosystem recovery and the reconstruction in ecologically fragile karst regions. This study examined the concentration of C-N-P and the related stoichiometry of live fresh leaves and leaf litter in three primary forests and compared them to data from three secondary forest communities in northwestern Guangxi. The results showed that the N and P contents of live fresh leaves in the six forest communities were greater than that of leaf litter. However, the N:P ratios showed opposite results, which indicated that the plant N reabsorption rate in this karst region was larger than that for P. The C, N, and P contents of live fresh leaves in the six forest communities were higher than those of leaf litter. In addition, the mean C and N contents of leaves in the three primary forests were higher than in the three secondary forests. However, P levels were slightly lower in the leaves of primary forests than in secondary forests. The results also revealed that the C:N, C:P, and N:P ratios of live fresh leaves from the six communities were all less than for the leaf litter. In addition, the order of the C, N, and P stoichiometric ratios for both live leaves and leaf litter in the six forest communities was C:P > C:N > N:P, and the C:N ratios of secondary forests were larger than that of primary forests for both live leaves and leaf litter. The C:P and N:P ratios of live leaves and leaf litter in the three secondary forests were all larger than the primary forests, which indicated that the secondary forests had higher growth rates. The N:P ratios of live fresh leaves in the three primary forest communities were between 13 and 15. The N:P ratios of live fresh leaves in the three secondary forest communities were between 11 and 12, which is between the upper and lower limit thresholds for N and P nutrient levels. Therefore, the N and P nutrient status of the three secondary forests (after 28 years of spontaneous recovery) has reached a relatively stable stage through long-term environmental adaptation. A significantly positive relationship was observed between the C:N and N:P ratios of both live fresh leaves and leaf litter. The N and P contents of all community species were positively correlated, and the N:P ratio was positively correlated with N content, but significantly and negatively correlated with P content.