Investigations were carried out of CH₄ emission and its δ¹³C values from a rice field under continuous flooding throughout the fallow and following rice seasons. Results show that in the fallow season CH₄ flux rose from April and reached a peak value, about 6.4 mg m^-2 h^-1, in June. After rice transplanting, CH₄ flux increased quickly at the beginning of the rice season and two peaks occurred in July and August, reaching 23.1 and 29.8 mg m^-2 h^-1, respectively, which was followed by a rapid decrease. Then another peak appeared during the final drainage before rice harvest. The total CH₄ emission in the fallow season amounted to 3.3 g m^-2, accounting for 8.9% of the annual total emission. On the other hand, δ¹³CH₄ (emitted) increased gradually from -51‰ to -44‰, and then dropped back to -56‰ in the late fallow season. After rice transplanting, δ¹³C value decreased from -62‰ to -68‰ firstly and then increased swiftly to -60‰, which afterwards remained unchanged for a relatively long time. Late in the season, emitted CH₄ became ¹³C enriched again. The impact of the final drainage on δ¹³CH₄ (emitted) was remarkable. The δ¹³C value of emitted CH₄ was heavier in the fallow season than in the rice season, because the fraction of CH₄ oxidized was higher in the fallow season (60%~90%) than during the following rice season (10%~80%). Within the whole observation period, the temporal variation of CH₄ flux was positively related to soil temperature (p<0.01), but negatively related to soil Eh (p<0.01) and to δ¹³C value (p < 0.05) as well.