Pitted courtyard cave dwellings were used as a long-term living form in Baishe village. After field measurements, the size of local pitted courtyards and cave dwellings had been mastered, and the variation of average annual rainfall and monthly rainfall had been analyzed. By the experiment, the changes of physical and mechanical indexes could be showed with different water contents. At the same time, based on the literature, the relationship could be established between rainfall and water content. Basis in the expression of room rock stress and the Mohr-Coulomb strength criterion, the stability of the cave dwellings could be analyzed under different water contents, and the definition could be found of safety factor of loess cave. Then, the stability variation of loess cave dwelling could be obtained in different rainfall, and the evaluation results are given.