应用三种丰富度指数，四种多样性指数，五种均匀度指数，进行了不同火因子对羊草草原植物多样性影响的研究。结果得出，灰分刺激与去枯作用明显提高了物种均匀度，加热作用则提高了物种丰富度，火烧的综合作用使得物种多样性显著增加。辛普森多样性指数计算的结果与其他指数的结果截然相反，不适于在此种情况下应用。 Three kinds of richness index, four kinds of diversity index and five kinds of evenness index were applied to study the effects of different fire factors on the plant diversity of Leymus chinensis steppe. The results showed that ash and de-decay significantly increased species evenness, while heating increased species richness, and the combined effect of fire increased species diversity significantly. The results of Simpson’s index of diversity are diametrically opposed to those of other indices and are not suitable for use in such situations.