In this work, the characteristics of decomposition gas generated from RDF has been studied in anaerobic and aerobic storage conditions for field storage of 42 days and constant temperature storage of 30 days, respectively. In order to verify the effect of water content for RDF storage, the experiments were also performed in anaerobic condition without water addition, water saturated condition and water impregnated condition, respectively. From this work, it was found that the oxygen concentration was severely changed in water impregnated condition and, the characteristic of CH4 and CO generation was different comparing with other two conditions. In field storage experiments, the concentrations of O2, CO2, CO and CH4 were analyzed with depth of RDF storage. After 10 days the concentration of CH4 was up to 0.17% at bottom, and was almost not detected at top. Therefore, it can be seen that the bottom of storage apparatus was more anaerobic condition.