Abstract: Determinations with Shimadzu CA-3 Automatic Bomb calorimeter show that after pregnancy stage,thecalorific values of rice stem,leaf and leaf sheath are decreased gradually.The calorific value of leafis positively correlated with rice yield, and its variation tendency is coincided with that of energy synthesis,accumulation,transportation and conversion in rice. Among N, C and ash.only the content of C is al-ways positively correlated with calorific values.