A walk-assistive apparatus may include at least one joint that corresponds to at least one joint of a wearer, at least one link that connects the joint, and is rotated in response to rotation of the joint, a spring that is mounted in the link or the joint so that a length of the spring is changed in accordance with rotation of the link or the joint, and a processor that controls the change in the length of the spring to compensate for a weight by gravity when the wearer walks. Accordingly, the walk-assistive apparatus and a method of controlling the walk-assistive apparatus may use a mechanical element such as a spring to reduce energy, and weight compensation having uniform performance may be performed even in an arbitrary posture.