Abstract:We analyzed soil samples from the plantation of Mixed plantation of Cumninghamia lanceolata and Mytilaria laosensis; C. lanceolata and Michelia macclurei and pure plantation of C. lanceolata in the Experimental Center of Tropical Forestry, Chinese Academy of Forestry. The soil aggregates were classified into >2 mm, 0.25-2 mm, and <0.25 mm fractions by a drysieving procedure. Soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) contents, and their stoichiometric ratios were calculated, and to examine the ecological stoichiometric characteristics of C, N and P within soil aggregates. The results showed that the coefficients of variation of SOC, TN and TP were 21.37%, 21.00% and 21.46%, respectively in the 0-10 cm soil layer and were 20.35%, 16.51% and 17.82%, respectively in the 10-20 cm soil layer. The spatial variation of TN was lower than that of SOC and TP but there were significant positive correlations among them. SOC and TN were distributed in the microaggregates and among of them had the greatest values in the C. lanceolata and M. macclurei plantation, however, the distribution of TP was relatively uniform among aggregates and ages. The coefficients of variation of C/N, C/P and N/P were 14.09%, 19.75% and 22.24%, respectively in the 0-10 cm soil layer and were 19.56%, 21.28% and 24.49%, respectively in the 10-20 cm soil layer. Variation of C/N was lower than that of C/P and N/P. Averaged C/P and N/P values in the macroaggregates were higher than that in aggregates of other sizes. C/N, C/P and N/P had good indication for SOC storage. The results showed that there was a lack of phosphorus in the mixed forest of C. lanceolata and M. macclurei. It was suggested that P should be supplemented in time to avoid the limitation of phosphorus on the sustainable utilization of soil.