The ecological stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) are the properties of ecosystem process and function. The seasonal dynamics of C, N and P in live plant-litter-soil system were measured in Phragmites australis and Cyperus malaccensis var. brevifolius wetlands from Minjiang River estuary. The results showed that seasonal averaged C, N and P concentrations were C>N>P in live plant, litter and soil. C and N concentrations were higher in live plant, litter than soil and the order of P concentration was uncertain between various plant organs and soil. Seasonal averaged C, N, P stoichiometric ratios were C∶P>C∶N>N∶P in live plant, litter and soil in the two wetlands. C∶N in P. australis wetland was in order of litter>live plant>soil, while they were in order of live plant>litter>soil in C. malaccensis var. brevifolius wetland. C∶P and N∶P were litter>live plant>soil in both wetlands. The C, N, P stoichiometric ratios may reflect the exchange of C, N, P and the ecological function of plant community.