The invention belongs to the technical field of difficult-to-process material cutting and processing, and relates to a micro-tooth design method capable of realizing alternative cutting of left and right cutting edges. The method can realize a processing way of alternative cutting of a right rotary cutting edge and a left rotary cutting edge on different sections of an effective cutting part of amulti-edge milling cutter, and guarantees continuous action that CFRP surface layer fibres bear axial force in different directions, so that the purpose of restraining occurrence of burrs of a high-speed milling carbon fibre composite material surface layer is realized. Micro teeth of a peripheral edge are designed, and structure parameters of a milling cutter are determined, so that a design method capable of realizing alternative cutting of the left and right cutting edges is guaranteed. The micro-tooth design method has very good universality and a high engineering application value, and can finally realize high-speed, stable and effective processing under great cutting dosage of carbon fibre composite materials.