An electric steering system (1) including a steering device (40), an actuating device (30) and a related method for controlling the electric steering system. The steering device (40) is configured to transmit steering signals in response to user operations. The actuating device (30) is configured to control the electric motor (301) to rotate a link arm (202) according to the steering signal, bringing the rotatable assembly (203) to rotate along an axis of the ship propulsion apparatus (20), thereby adjusting an orientation of the propeller (2034). The actuating device (30) is rotatably coupled to an end of the link arm (202).