Abstract:The paddy rice in the field experiment, grown at three different altitude localities, viz. Yuanjiang (north tropic type about 400 m altitude) , Yuxi (middle subtr-opic type about 1600 m altitude) and Dali (north subtropics type about 2000 m altitude) in Yunnan provice in 1988, had been fed with the 14C during the booting and the grain filling stage, respectively.All the samples had been collected at the yellow ripe stage.