A finite difference analyzing method of a pile is provided to consider a lateral flow quantity as well as a lateral flow pressure based on a non-linear subgrade reaction theory capable of reflecting non-linearity of soil. One mathematical formula considering the lateral flow pressure or another mathematical formula considering the lateral flow quantity is selected as a finite difference model of the pile constructed in the soil(110). The lateral flow pressure or quantity, a length, diameter, bending stress, a boundary condition for a pile head and tip are inputted to the selected mathematical formula(120). A subgrade reaction coefficient for each component is calculated by considering cohesive soil, multilayer soil, and depth of the ground, and at least one of horizontal displacement, inclination, bending moment, and shear force of each component is calculated(150).