A hydraulic adaptively-adjustable foot is characterized in that an upper opening of a bottom shell is fitted with an upper cover, a piston body is arranged inside the bottom shell, a piston sealing ring is mounted between the outer periphery of the piston body and the inner wall of the bottom shell, a return spring is arranged between the bottom of the piston body and the bottom shell, and the bottom end of a support post is passed through a center hole of the upper cover and hermetically into the bottom shell. The bottom center of the projecting edge of the bottom end of the support post is provided with a channel; a steel ball return spring is arranged in the channel; the center of the bottom of the piston body is provided with a spring channel; the top end of the steel ball return spring is arranged in the spring channel; the axial center of the spring channel is provided with a hydraulic oil passage; a steel ball is arranged between the top end of the hydraulic oil passage and thebottom end of the steel ball return spring. The hydraulic adaptively-adjustable foot has the advantages that hydraulic oil flows in upper and lower cavities of a piston via the hydraulic oil passage controlled via the steel ball, the hydraulic oil and the return spring coact, along with stabilized weight of a support, such that the height of the foot herein is automatically adjusted; the foot herein is simple and compact in appearance and suitable for repeated adjusting.