Abstract: This Paper studied the growth law of Leymus chinensis and effect of environment factors on the Leymus chinensis grassland in the northeast China with the grertheory. The results indicated:the growth of Leymus chinensis population has adistinCt seasonal variation, it grows best from July to August, the growth rate isfrom 0.2-0.403g/m²·d. Among nine environment factors, Hydrolyted nitrogen, quick acting postassium, active organic matter, temperature, PH and effective Phosphorus to Leymus chinensis growth kaye the best connected coefficients, those of hydrolyted nitrogen, quick acting posstassium and active organic matter arepromoted factors, PH is restrictive factors. The best model of Leymus Chinensisgrowth is y=4.74X₁+6.15X₂+2.48X₃-73.64.

Key words: Leymus chinensis grassland, Leymus chinensis population grouth, Environment