The long-term mowing has broken the long-term material cycle of the grassland ecosystem，and the nutrient input and output have been out of balance，causing the soil to become barren.This paper took natural mowing of Leymus chinensis meadow grassland in Hulunbeier as the research object to study the changes of soil nutrients and stoichiometry of different fertilization treatments on Leymus chinensis mowing grassland，and to explore the optimal plan for improving the effect of fertilization on degraded Leymus chinensis mowing grassland.It could provide theoretical guidance and reference for the restoration and improvement of degraded grasslands.The results of the study showed that as the year of fertilization increased，the total carbon and total potassium content of the soil decreased year by year，while the soil available nitrogen and available phosphorus increased year by year.High-concentration fertilization treatment was beneficial to increase 0 ～ 10 cm layer soil total nitrogen and 20 ～ 30 cm layer soil total potassium content(P<0.05)，while 0 ～ 10 cm layer soil total carbon and total phosphorus content，10 ～ 20 cm layer soil total carbon，20 ～ 30 cm layer soil total nitrogen and total phosphorus content of the low-concentration fertilizer treatments were the highest；medium-concentration fertilization and high-concentration fertilization treatments significantly increased the soil available phosphorus content of 0 ～ 10 cm layer，while low-concentration fertilization treatments significantly increased the soil available phosphorus content of 10 ～ 20 and 20 ～ 30 cm layer(P<0.05)；With the increase of fertilization years，the soil C ∶ N of different soil layers decreased significantly year by year.In 2017，the soil C∶N of different soil layers was the lowest.Among them，the soil C∶N under the high-concentration fertilization treatment was significantly lower than that of the control treatment(P<0.05)；soil C∶P decreased significantly year by year，of which the soil C∶P of 0 ～ 10 cm layer in 2016 was significantly lower than other years(P<0.05)；the change of soil N∶P was relatively stable in the late fertilization period，0 ～ 10 and 20 ～ 30 cm layer soil N∶P was significantly lower than the first year(P<0.05).Fertilization is used to supplement the content of restricted elements in the soil and affects the stoichiometric characteristics of soil and plants，and determine the optimal stoichiometric ratio of vegetation and determine the types of restricted elements.The accumulation of fertilizer efficiency reduced the soil stoichiometric ratio，and high-concentration fertilization treatment(N 10.5 g·m-2+P 5.1 g·m-2)was beneficial to reduce soil C ∶ N.Nitrogen is still a major factor restricting the growth of plants in this area，especially in years when rainfall is scarce.