The invention relates to the field of unmanned underwater robots, in particular to a light unmanned underwater robot steering gear. The light unmanned underwater robot steering gear comprises horizontal rudder blades, vertical rudder blades, a horizontal rudder fork, a vertical rudder fork, a horizontal rudder fork connecting rod, a vertical rudder fork connecting rod, a horizontal steering engineand a vertical steering engine. The horizontal rudder fork and the vertical rudder fork are perpendicularly arranged in the tail portion of an unmanned underwater robot, a bent part is arranged on the middle portion of the vertical rudder fork, the middle portion of the horizontal rudder fork is arranged in the bent part, the horizontal steering engine is connected with the horizontal rudder forkthrough the horizontal rudder fork connecting rod, the vertical steering engine is connected with the vertical rudder fork through the vertical rudder fork connecting rod, the two ends of the horizontal rudder fork are connected with the horizontal rudder blades, and the two ends of the vertical rudder fork are connected with the vertical rudder blades. The vertical rudder blades and the horizontal rudder blades are controlled through the two specially-shaped rudder forks, the two rudder forks are arranged perpendicularly and cannot interfere in each other in the rotating process, and the installation space is effectively saved.