In order to solve the problem of repairing the underwater part of large ships,an underwater bionic robot was designed.The 3D mechanical model of the bionic robot was established by using SolidWorks software,the control system was designed,and the mechanical characteristics of the robot working underwater were analyzed.When the bionic robot was working,sensors such as ultrasonic and gyroscope were used to convert the detected underwater environment parameters into electrical signals,which were sent to the STM32 controller in real time;the STM32 controller was used to processes various signals according to the preset algorithm;by using the STM32 controller,the commands were send to control the propeller,camera and other executive components,so the automatic operation of the bionic robot was realized.The results show that the bionic robot is stable,sensitive,without water leakage and uncontrollable situation,and it can achieve the expected goal.