Monte Carlo method is used to establish a random fluctuation surface model by considering the random ups and downs characteristics of the outer surface of the cast-in-place pile. Direct shear tests of the pile-soil random fluctuation surface under different normal stress and fluctuation height are carried out. The effects of normal stress and average fluctuation height on the shear behavior of the cast-in-place pile-soil random fluctuation interface are analyzed, such as shear strength, failure mode, shear stress-displacement relationship, etc. The results show that: Radial fluctuation of the outer side of the cast-in-place pile agrees with the Gaussian distribution, and the fluctuation height is mainly concentrated in the range of 0 ~ 8% of the pile diameter. With the increase of the fluctuating height, the number of soil particles embedded in the concave part of the pile-soil interface increases. The failure mode of the pile-soil random fluctuation interface gradually develops from pile-soil interface sliding shear failure to internal shear failure of the soil. The cohesion and internal friction angle of the pile-soil random fluctuation interface also increase, and the shear stress-strain curve of the random fluctuation pile-soil random fluctuation interface gradually approached to the shear stress-strain curve of soil.