The embodiment of the invention discloses a cutting depth prediction method and device suitable for abrasive belt grinding and polishing of a complex curved surface robot, and the method comprises thesteps: obtaining the stress distribution between a contact wheel and a workpiece through a finite element analysis method, correcting a Hertz contact model between the contact wheel and the workpiecethrough the stress distribution, and obtaining a stress distribution model; obtaining a plurality of path points on each path obtained after the path planning of the workpiece; and obtaining a cutting depth prediction model of each path point by combining the grinding and polishing time and the feeding speed of each path point according to the stress distribution model, and determining parametersof the prediction model based on the actual cutting depth. According to the method, the accurate stress distribution model can be obtained, and the cutting depth prediction model is further obtained,so that the normal force and the grinding and polishing speed in the grinding and polishing process are accurately controlled, the machining precision of the workpiece better meets the actual requirement, and the generation of waste materials is reduced.