The invention relates to an underwater robot for detecting and cleaning pollutants in water. The underwater robot comprises a robot shell, a power motor is fixedly arranged on the side face in the robot shell, a rotary shaft of the power motor is connected with a power impeller, the power impeller penetrates through the side wall of the robot shell, and the power impeller is in rotational and sealing connection with the side wall of the robot shell. The robot shell is internally provided with a charging port, a battery, a controller and a signal receiver, wherein the charging port, the controller, the signal receiver and the power motor are electrically connected with the battery, the signal receiver is electrically connected with the input end of the controller, the signal receiver and the power motor are electrically connected with the output end of the controller, and the side, away from the power motor, in the robot shell is fixedly provided with balancing weight. The underwater robot has the advantages that the robot has the function of cleaning the underwater pollutants, the underwater pollutants can be classified and collected, and convenience is brought to late research anddetection.