Abstract: The root, stem, leaf and inflorescence of Elymus sibiricus cv. Chuancao No.2 population were determined at the flowering stage of the third year to elucidate the effect of row space on the quantitative trait of components, biomass structure, accumulation and distribution proportion of energy. There were highly significant differences in total tiller and the ratio of fertile to total tiller between different row spacings, and significant differences in eustipes length and number, and natural height of each tiller, but there was no significant difference in leaf length, width and number of tillers. Significant effects of row space were found on the depth and distribution range of root, length of sear stalk, ear number of fertile tillers, and the biomasses of leaf, stem, root, and inflorescence. The importance showed a descending order of stem> leave> root > inflorescence. No significant differences were found in energy value of single leaf, stem, root and inflorescence between row spaces, but significant differences were found in energy accumulations of leaf, stem, root and inflorescence in the order stem> leaf> inflorescence> root. There was a significant difference in energy distribution among row spaces: leaf > stem > inflorescence > root. The 30 cm row space is optimum for forage production, and 60 cm is the best for seed yield.