The characteristics and biolnaical mechanism of methane reliase in paddy soil were studied by the soil column and in situ field methods.The results obtained showed that the amounts of methane released were the highest during full-tillering stage of both early and late rice; the amount of methane released was higher during night and morning and lower during afternoon;fertilizers could stimulate the release of methane in paddy soil and the methane release of organic manure plot was more than that of urea plot; there active part of methane formation was the root system which was undisturbed and combined,closely with soil; more than 80% of mrthane was released by rice plants; methanogenie bacteria adhered to surfaee of roots.The result also showed that the amounts of methanogenic bacteria,anaerobic celluloclastic and methane-oxidizing bacteria as well as TVFA were higher in rhizosphere soil were than in non rhizosnhere soil.