Abstract:This paper is based on the theory of Harper′s(1977) modular structure, explored the features of energy value and the method of measuring energy value of Neosinocalamus affinis clone population in the surburbs of Nanchong at three levels: the unit of modular construction, the ramet and the clone.In the Neosinocalamus affinis clone population, the mean AFCV of each unit of modular construction is as follows, root 15349.42J/g, rhizome 16372.92 J/g, culm 17106.06J/g, branch 18111.99J/g and leaf 19451.90J/g; the AFCV of the ramets of Neosinocalamus affinis is increasing with age class; the allocation to the total energy (AFCV) at the ramet level are that 1 age class is 16.47%, 2 age class is 25.76%, 3 age class is 36.32%, 4 age class is 13.08% and 5 age class is 8.37%. The changes of the energy value are related to the oxygen pressure in the oxygen bomb calorimeter, which measures thermal value with combustion method at constant volume. The energy value calculated with the experience formula is bigger than with the way of Leiro check curve; It is more accurate if the energy is expressed with AFCV than GCV, and the AFCV is bigger than the GCV.