Abstract: The aims were to study the dynamics of growth and nutritional changes of Vicia Sativa, and obtain the optimal clipping period. Vicia Sativa 5-1-5 was used as the sample, the changes of plant height, growth rate, material accumulation, yield components and its compositions were studied. The nutrition value was also assessed. The results indicated that the dynamic growth of Vicia Sativa fit the Logistic model. The growth rate was slow in the seedling stage, and became the fastest from the branching-later stage to squaring stage, it was the critical period of vegetative forming. Biomass and the ration of stem to leaf increased gradually in the branching-later stage, but the palatability and nutritive value declined. The fresh matter and the dry matter reached the maximum in the fruiting period and the mature-later stage, respectively. The fresh matter in the fruiting period, CP, CA, CF, EE, NFE, TDN was 17.2, 0.5, 0.33, 1.29, 0.11, 2.17, 2.73 t/hm2, respectively. The dry matter in the mature-later stage, CP, CA, CF, EE, NFE, TDN was 4.71, 0.41, 0.34, 1.40, 0.10, 2.49, 2.83 t/hm2, respectively. In summary, 76-88 days after sowing was the optimal clipping period. It was suggested that Vicia Sativa should be harvested in blooming stage or fruiting-early stage in the practice.