Abstract: Abstract: （OBJECTIVE）FACE (free air carbon dioxide enrichment) technology is capable of providing a means by which the environment around growing plants may be modified to realistically simulate future concentrations of atmospheric CO2. The plant growth and yields in plant species can be enhanced under FACE. Identifying the response of metabolism of carbohydrate during grain filling to elevated CO2 will be useful for us to develop higher yield cultivars, adapting to future CO2 enriched at current CO2 concentration （METHOD）The accumulation and transfer of carbohydrate during grain filling and yield of IR24 were studied under FACE. （RESULTS）The results showed carbohydrate conten of stem under FACE was always higher than that under CK during grain filling, but the rate of carbohydrate transfer under FACE was lower than that of CK during 15d~30d. Additionly, FACE significantly increased yield compoments of IR24. （CONCLUSION）The above results showed FACE enhanced yield and the accumulation of carbohydrate in stem of rice, but the transfer rate was different during grain filling.