Plum-blossom pile is a novel kind of new cross-sectional shaped pile, and at present, there is no relevant research on the bearing characteristics of plum-blossom pile under lateral load. Based on the theory of circular hole expansion, the calculation method of soil displacement around plum-blossom pile in sand during pile sinking is established. With considering the special-shaped effect of plum-blossom pile section, the soil squeezing displacement in the positive direction of coordinate axis is obtained by using the principle of coordinate transformation and superposition on the basis of Hooke’s law. The differential equation of pile deflection curve is derived by using m method and its difference solution, and the reliability of the established theoretical method is verified by comparing with the experimental results. The results show that the horizontal displacement of soil between plum-blossom pile and circular pile with equal cross-section is similar. With the increase of horizontal load, the horizontal displacement first increases and then decreases, and the horizontal displacement of soil near plum-blossom pile is about 73.5% of that of circular pile with equal cross-section. The vertical squeezing force of plum-blossom pile on the soil facing surface under horizontal load is small, and the vertical displacement fluctuates with the increase of horizontal load. With the increase of horizontal load, the horizontal displacement of soil in the middle of plum-blossom pile first increases and then decreases, and the maximum horizontal displacement is about 75% of that of circular pile with equal cross section.