Abstract: This paper examines the Lishi loess of Guanzhong region. It develops a soil disintegration test instrument for doing the flooding experiment of indoor small size. It measures soil disintegration process parameters to explore Lishi loess rate characteristics of disintegration in the region. It aims to offer a reference for time prediction of Lishi loess slope instability in the region. The results reveal some phenomena and laws of the disintegration process. Under different flooding conditions, the whole process of Lishi loess can be divided into rapid disintegration stage from the experiment beginning to formulate flooding depth and disintegration stabilization phase after flooding water. Loess body size has a certain relationship with rate of disintegration, the immersion depth and contact area. The rates of disintegration have broken line relationship with time. The disintegration rate is reduced rapidly to about 0.21~0.25kgmin-1 after a peak from the experiment beginning to formulate flooding depth. Then the disintegration rate is fixed in 0.08~0.14kgmin-1 until after flooding water stability. When loess sampling extent of flooding is fixed, with the increase of immersion depth, the stabilization of the soil disintegration rate increases linearly, and presents a linear correlation.