Rainfall is one of the important factors that induce landslide sliding and landslide stability.At present,the research on the influence of rainfall on the tunnel landslide orthogonal system without the supporting structure is still lacking.In order to study the action mechanism of rainfall on the tunnel landslide orthogonal system under different intensity of rainfall,and study the characteristics of slope deformation and the stress characteristics of the tunnel without the supporting structure,the influence mechanism of rainfall for the Tunnel-Landslide Orthogonal system by large geological mechanics simulation model test is researched.With the four different stages of rainfall,the changing characteristics of longitudinal of tunnel and the variation characteristics of circumferential stress of tunnel with different cross sections,and the changing characteristics of the displacement of the sliding body at different locations and different cross sections also are analyzed.The results show that:(1) The rain can lead to the cross-sectional of slope broke,and form a new glide plane which result in the landslide slipped.(2) With the increasing of water content of sand,the strain of tunnel has obviously sudden changed,and the longitudinal strain of tunnel near the mountain is bigger than the longitudinal strain of tunnel near the river.(3)Rainfall makes stress of the tunnel uneven change;And the stress of tunnel bottom is greater than the stress of the top,the stress near the mountain is larger than the stress near the river under the tunnel landslide orthogonal system,and shows that necessary drainage measures are indispensable.And it is indicated that the rainfall can cause the movement of the sliding body,cause the uneven stress and deformation of the tunnel,which is very unfavorable to the safety of the tunnel structure.This experiment can provide some reference for the landslide and tunnel anti slide design in the abundant water area.