The invention discloses a walker capable of adjusting the length of a walker body by a gear piece. The walker capable of adjusting the length of the walker body by the gear piece includes a front walker body and a rear walker body, wherein a gear adjusting mechanism is used for connecting the front walker body and the rear walker body. The distance between the front walker body and the rear walkerbody can be adjusted by adjusting a matching position of the gear adjusting mechanism. The gear adjusting mechanism comprises a rack and a gear piece matched with the rack in a limited mode. The gearpiece is arranged on the rear walker body, and the front end of the rack is connected with the front walker body, and the rear end of the rack is matched with the gear piece. When the gear piece rotates to drive a clamping gear on the rack, the movement of the rack is driven by the clamping gear, so that the distance between the front walker body and the rear walker body can be adjusted. The walker capable of adjusting the length of the walker body by the gear piece can adapt to the use by more people.