In order to improve the stability,sensitivity and anti-interference ability of the underwater robot in the complex underwater working environment,a fuzzy PID algorithm was proposed to optimize the original control system of the underwater robot.The mechanical structure of the underwater robot and the hardware structure of the control system remained unchanged,and the fuzzy PID control of the underwater robot was only performed through the software program.When the underwater robot was working,various sensors converted the environmental parameters of the scene into electrical signals,which were fuzzified by the preset fuzzy library and sent to the STM32 controller;the STM32 controller processed the fuzzy signals according to the preset program.After processing the de-fuzzied electrical signal,it was sent to the executive element,thus realizing the fuzzy PID control of the underwater robot.The simulation results of MATLAB/Simulink and underwater test results show that compared with the classical PID algorithm,the underwater robot optimized by the fuzzy PID algorithm has more sensitive response,more stable system,stronger anti-interference ability,and the expected effect is achieved.