Static-chamber in field and alkaline absorption methods were used to measured the CO₂-release rates of soil respiration and litter decomposition of meadow marshes in Sanjiang Plain. The effects of environmental factors on CO₂-release were discussed and then the contribution of the litter decomposition to the total CO₂-release was estimated. Two types of D. angustifolia meadow (XZ and XD) were selected to synchronously observe the CO₂ release and the temperatures of air and soil in the growing season. The results showed that the CO₂ release temporally varied (p<0.05). The rates of soil respiration in the XZ and XD were higher in July and August and the daily averages were 6.08g•m-2•d^-1 and 9.26g•m-2•d^-1, respectively. However the rates of CO₂-release from litter decomposition were higher in June and the daily averages were 1.76g m-2•d^-1 and 3.10g•m-2•d^-1, respectively. The results also showed that the total CO₂-release and release from litter decomposition were different between two sites of XZ and XD (p<0.05). There were a significantly exponential relationships between the soil respiration and soil temperature (p1<0.01, p2<0.05) and between the total CO₂-release and air temperature (p1<0.01, p2<0.01) in sites of XZ and XD. Multi-analysis showed that temperatures of air and soil combined with monthly accumulative precipitation could effectively explain the changes of the total CO₂-release (R12=0.967, R22=0.741) and soil respiration (R12=0.548, R22=0.893) in sites of XZ and XD, respectively. Based on the rates of CO₂-release from different carbon pools, the contribution of litter decomposition to the total CO₂-release was estimated to be 31% and 35% in the XZ and XD, respectively. This study demonstrated that during the transferring process from the plant carbon pool to the soil carbon pool, the litter in marsh as important release sources of carbon should not be neglected.