The invention discloses an unmanned ship sensor stable lifting device. During the working process of an unmanned ship, a sensor installed at the bottom of the unmanned ship has the effects of receiving and sending signals, detecting depth, avoiding obstacles and the like. When the speed of the unmanned ship is too high or the flow speed of the water body is larger, the sensor needs to work uninterruptedly, and therefore the protection of the sensor and the stability of the sensor are particularly important. The unmanned ship sensor stable lifting device comprises a sensor storage chamber installed on a first-stage deck, and a ball screw penetrates through the sensor storage chamber, the first-stage deck and a second-stage deck. The lower portion of the ball screw is connected with the sensor, the upper portion of the ball screw is connected with a bevel gear, and a driving motor installed on the second-stage deck is connected with a shaft through a coupler. Along with the operation ofthe motor, the ball screw is changed into linear motion from rotary motion, and then the sensor is driven to do reciprocating linear motion. The unmanned ship sensor stable lifting device not only canensure the stable operation of the sensor, but also can protect the sensor, thereby improving the working efficiency of the sensor.