Studies on energy allocation to growth and reproduction in Leymus chinensis population show that the average calorific value of modulus was decreased in the order of ear > leaf sheath of vegetative shoot > leaf sheath of sexual shoot > leaf of vegetative shoot > stem of vegetative shoot > stem of sexual shoot > leaf of sexual shoot > litter, and the energy allocation rate of vegetative and reproductive growth was in the order of vegetative shoot > rhizome > litter > sexual shoot. The dynamics of energy allocation rate of modulus was different with seasons. Among all reproductive stem modulus, the rate of energy allocation to stem and leaf sheath of sexual shoot was higher than that to ear and leaves.