|In order to further solve the problems of much cutting energy loss, power mismatch and low production efficiency in the production process of drum chipper. Based on the theory of fracture mechanics, combined mode I, II and III fracture criteria. Considering the impact of annual ring on the fracture of wood. The dynamic problem of rotating cutter was transformed into fracture analysis of wood. The cutting process of cylindrical crack wood was analyzed, the crack extension model was determined and the mechanical model was constructed, the relation between cutting force and cutting parameters was derived and studied. By making full use of the MATLAB software, the relationship between cutting angle, wood radius, cutting thickness and cutting force was analyzed, to build models for in-depth research. The cutting energy was optimal when the cutting angle θ=π/4 and the crack polar angle φ=2π/5.