Abstract: In order to study the law of rain-induced loess landslide-mudflow, this paper designed six sets of laboratory model tests, analyzed the macroscopic deformation process, hydrological process and displacement change law of rain-induced loess landslide-mudflow, discussed the influence of different rainfall intensity, single cumulative rainfall and slope on landslide development, and established the threshold curve when landslide and mudflow occurred. The results show that there are two failure modes of loess slope under extreme rainfall conditions: sliding and sliding transflow. When short-term heavy rainfall occurs, the tensile structural surface of the fractured slope is filled with water, the strength of the sliding surface decreases, and the sliding body slides in the form of a block. The whole sliding process shows the characteristics of long-term creep superposition intermittent accelerated sliding, and the critical threshold curve is as follows: I=59D^−0.67. When continuous rainfall occurs, a strong fissure area will appear on the slope with progressive sliding, and pore water pressure in this area will continue to rise. The water-rich slope will experience liquefaction flow, which is characterized by continuous high speed. The critical threshold curve is E=200−2.5I.