Soil samples under plastic shed vegetables in Longdong and its surrounding areas on the Loess Plat- eau were analyzed.Results showed that both soil salt accumulation and acidulation in topsoil were evident and the amounts of main soil n ut rients are increased.The reasons for the change are the over applied fertiliz- er, poorly added organic manure, continuous cultivation, irrational irrigation, etc.We should increase or- ganic man u re, limit mineral fertilizer application, improve fertiliiing practice, perform irrigation and drainage scientifically, and u ndertake rational rotation in the future.