Abstract: Mud cake formation on the cutterhead of tunnel boring machines during construction in cohesive strata can result in high risks and low efficiency of manual cleaning. A mud cake flushing robot system for tunnel boring machines is developed to achieve safe and efficient cutterhead cleaning. Firstly, the formation mechanism of mud cakes during tunnel construction was analyzed, and the system scheme of the mud cake flushing robot was designed. Secondly, the key factors affecting mud cake flushing by high-pressure water jets were investigated based on fluid mechanics theory, and the influence of nozzle diameter on the jet flow field was analyzed using computational fluid dynamics (CFD) simulations. Subsequently, a mud cake flushing test platform was established to investigate the effects of key high-pressure water jet parameters on flushing performance. Finally, the effectiveness of the proposed system was verified through field application. The results demonstrate that the mud cake flushing efficiency is significantly improved after optimizing the configuration of high-pressure water jet parameters, satisfying the requirements of shield tunnelling operations.