Leaf tissue turnover of Leymus chinensis and Phragmites communis after grazing was studied by application of theory and method of tissue turnover in this paper. The results showed that the number of living leaf of P. communis was larger than that of L. chinensis, but the length of living leaf of L. chinensis was larger than that of P. communis during the whole growth period. Both of the leaf appearance rate and the leaf elongation rate of L. chinensis and P. communis were largest at first, and then they decreased gradually. The rate of leaf wither and leaf senescence were in the converse trend. The leaf lifespan of P. communis was shorter than that of L. chinensis. The velocity of leaf tissue turnover of P. communis was faster than that of L. chinensis. There would be a great loss if the leaf tissue of L. chinensis were not used in time. The quality of grasslands could be improved by different utilization ways and periods.