Abstract: Studies on laws of methane production in paddysoil have been carried out and the results show that(1) tempera-ture has a significant influence on methane production andmethane production rates increase by about 3 times with a rise of 10℃in temperature;(2)two peaks of methane production ap-pear after transplantation and before harvest respectively for bothearly rice and late rice,methane production rates are lower atmiddle growing stage ;(3)vertical distribution of methane pro-duction rates in paddy soil coincides with that of organic acid contents;(4) methane production rates in paddy soil with rice plants are much higher than those without rice plants and the dif-ference is getting more and more significant with the tice growth;(5)more than 80 % of the methane produced in paddy soil is re-oxidized in the course of transportation to the atmosphere i.e. less than 20%of the methane can be emitted to the atmosphere. 

Key words: paddy field, head-space gas chromatography, methane production rate, seasonal variation, vertical distribution