Abstract: According to small deflection theory, a mechanical model for pipeline vacancy caused by loess collapse, washout and landslides is establishes in the article. Considering the effect on pipelines such as pipe's deadweight, coating weight, the weight of the medium piped, temperature stress and soil's cohesion, various methods for load calculation are provides hereinbefore and ANSYS software is used to calculate the stress distributed over different length of pipeline segments vacant. The maximum Mises stress and displacement values as well as their corresponding positions are found out finally,