The invention discloses an ultra-short baseline positioning method based on an adaptive unscented Kalman filter. The ultra-short baseline positioning method based on the adaptive unscented Kalman filter comprises the following steps: step 1, an ultra-short baseline is used for underwater positioning; step 2, the position information of a mother ship and the position information of an underwater robot positioned by using the ultra-short baseline are sent to the underwater robot through a photoelectric hybrid cable; step 3, the underwater robot receives the position information sent by the mother ship; and step 4, the underwater robot fuses the position information with the carried accelerometer, inertial navigation, depth gauge and other sensors, and attenuates the noise according to the adaptive unscented Kalman filter. The ultra-short baseline positioning method based on the adaptive unscented Kalman filter has simple operation, and can improve the underwater positioning accuracy of the underwater robot by fusing the multiple sensors and the ultra-short baseline positioning information.