Abstract: December 2007, mixed leaf litter decomposition with N and P additions in Cunninghamia lanceolata and Castanopsis fissa plantations of South China was studied at Yunyong forest farm of Gaoming district, Foshan, Guangdong. Completed random was introduced to N, P and N + P addition treatments, and the plantations with no fertilizer as the control. The findings showed that decomposition rate of mixed leaf litter under C.lanceolata and C.fissa plantations was postponed by N addition and accelerated by P and N + P addition treatments. Decomposition rate of mixed leaf litter under the C.fissa plantation was faster than that under the C.lanceolata plantation. Twenty-four months after the decomposition, the N content of mixed leaf litter with N and N + P additions was greater than their initial N content in the C.lanceolata plantation, whereas that with all treatments was significantly smaller than their initial N content in the C.fissa plantation. The P content of leaf litter with P and N + P additions was significantly greater than its initial P content in the C.lanceolata and C.fissa plantations. The K content of leaf litter fluctuated greatly during the whole decomposition period.