Abstract: Investi gations on soil fauna are made in the natural reserve of Xilinguole grassland.Indifferent habitats of the grassland ecosystem,the species and quantity of soil fauna arenot only varied with the type and properties of soil,but also influenced comprehensivelyby other ecological factors.Therefore,the species and quantitative distribution of soll faunacan reflect the characteristics of different habitats to a certain extent.They are suggestedto be taken as the indicator for the fertility level of different soil types in the grassland ecosystem.

Key words: Eco-construction, Ecological security, Region, Orderly human activities, Landscape ecology