SPSS cluster analysis and CANOCO ordination method were applied to discuss the relationship between vegetation and its environmental factors in the west slope of Helan Mountain. The results show that the vegetation community can be divided into three types, namely Salsola passerina -Reaumuria soongorica community, Stipa breviflora - Stipa grandis community and Prunus mongolica-Ulmus glaucescens community. Canonical correspondence analysis suggests a significant difference on the relationship between vegetation and environmental factors. In Salsola passerina -Reaumuria soongorica community, the first ordination axes explains the salinization gradient, along the order of Caragana tibetica community，Salsola passerina-Oxytropis aciphylla community，and Reaumuria soongorica-Salsola passerine community，soil alkalization increases. The second ordination axis explains soil structure gradient, along the order of Caragana tibetica community, Reaumuria soongorica-Salsola passerina community and Salsola passerina community, soil texture becomes coarser. In the Stipa breviflora-Stipa grandis community, the first ordination axis indicates the soil water gradient, and the second ordination axes explains hydrothermal coupling gradient. In the Prunus mongolica-Ulmus glaucescens community, the first ordination axis explains the soil pH gradient, along the order of Ulmus glaucescens-Prunus mongolica community, Prunus mongolica-Potentilla fruticosa community, and Potentilla fruticosa-Prunus mongolica community, soil pH value reduces. The second ordination axis explains soil structure gradient, along the order Prunus mongolica-Ulmus glaucescens community, and Prunus mongolica-Potentilla fruticosa community, the contents of silt and clay increase, and soil texture suggests a fine trend.