Abstract: A mechanical foot includes a mechanical ankle joint including a leg portion configured to be fixed to a patient's leg, a foot portion configured to be fixed to the patient's foot, and a revolute. The leg portion and the foot portion are connected through the revolute in a manner of being rotatable relative to each other. The revolute includes a foot connecting portion connected to the foot portion and a leg connecting portion connected to the leg portion, and the foot connecting portion and the leg connecting portion are connected in a manner of being rotatable relative to each other. The revolute further includes a first elastic element having one end connected to the foot connecting portion, and the other end connected to the leg connecting portion, so that a force maintaining the patient's foot substantially horizontal is provided through the revolute at a position of the mechanical ankle joint.