The invention provides a flaky graphite electrode machining technique for an injection mold. By adoption of the flaky graphite electrode machining technique for the injection mold, the problems that during numerical-control milling of thin-walled graphite electrodes with reinforcing rib sizes, the upper ports of semi-finished electrodes are prone to brittle breakage frequently, and the sizes are not standard are solved. From the thought angle of systematic techniques, reasonable machining techniques are sought for discussion on the aspects of pretreatment of graphite materials, reasonable selection of tools and machining parameters, reasonable arrangement of numerical-control milling steps, selection of a special high-speed graphite machining machine, compiling of numerical-control programs and the like, a specific machining method and specific technological parameters are given, and a beneficial reference is provided for mold enterprises for graphite electrode machining; and automatic production can be achieved, production cost of similar electrodes is reduced effectively, and working efficiency is improved.