The invention relates to the technical field of classifying crusher design, in particular to a three-dimensional dynamic design method for a classifying crusher. The design method comprises the following steps that firstly, the tooth roller diameter, the tooth roller length, the crushing tooth shape and the installed power of the crusher are primarily designed; secondly, static simulation is carried out on the structural safety of crushing teeth; thirdly, static tests are carried out on the structure of the crushing teeth; fourthly, whole machine mode analysis and dynamic simulation are carried out; fifthly, dynamic tests of the whole machine are carried out; sixthly, optimum structure design is carried out based on an orthogonal test method. The design method is more systematic, standard and efficient, the research and development costs are greatly reduced, the research and development speed is accelerated, on the premise of guaranteeing the safety performance and the reliability of the crusher, the equipment is light, and the cost performance is improved.