Abstract: The displacement and earth pressure characteristics of the vegetated slope and the bare slope in a cold and arid region under rainfall condition are explored to quantitatively analyze and evaluate the slope protection effects of plants. The self-built test area is located in Qinghai University of Xining Basin. Through in-situ rainfall simulation to the bare slope and the slope vegetated with Caragana Korshinskii. kom, the earth pressure values of the two slope surfaces are analyzed. Changes in the displacement in both the horizontal and vertical directions are analyzed as well. The stability of two kinds of slopes in the test area is evaluated. The results show that as to the slope vegetated with C. Korshinskii before and after the rainfall simulation in layer a (below slope surface 0~20 cm) and layer b (below slope surface 20~40 cm), the increase rates of soil moisture are reduced by 32.03 % and 13.63 % compared with the bare slope, which indicates that the plant stems and leaves play an important role in rainfall interception. After the rainfall simulation, the average earth pressures of the two slopes are slightly higher than that before the rainfall simulation, the average earth pressure of the bare slope is 0.125 kPa higher than that before rainfall and the average earth pressure of the slope vegetated with C. Korshinskii is 0.129 kPa higher than that before rainfall. The surface deformations in both the horizontal and the vertical directions of the bare slope before and after rainfall are 0.196 cm and 0.158 cm, respectively, and the slope vegetated with C. Korshinskii before and after rainfall are 0.031 cm and 0.027 cm, respectively. The results also show that the plants can significantly reduce the deformation of slope surface and improve the stability of the slope surface. The results of this test have theoretical and practical significance in preventing the occurrence of geological disasters, such as soil and water loss and shallow landslide in the test area.