The invention discloses a multifunctional drilling and milling mechanism. The multifunctional drilling and milling mechanism comprises a main shaft head and a main shaft box, wherein the main shaft head comprises four drilling power heads, a main shaft box shell, two milling power heads, a mouse-tooth disc and a cutter disc gear, wherein the four drilling power heads and the two milling power heads are uniformly distributed along the circumferential direction of the cylindrical profile of the main shaft box shell, and are arranged on the main shaft box shell by rolling bearings; the mouse-tooth disc is arranged on the end surface of one side of the main shaft box shell, and the cutter disc gear is arranged on the center of the main shaft box shell; the main shaft head is connected to one end of the main shaft box by virtue of the mouse-tooth disc; the main shaft box comprises a shaft VIII, a shaft II, an indexing main shaft, a main transmission shaft, a shaft X, a shaft III, a shaft IV, a shaft IX, a worm shaft VI, a shaft VII and a turbine shaft which adopt the main shaft box body as support, as well as a lead-screw support, a connecting rod mechanism and a main driving clutch device. The multifunctional drilling and milling mechanism disclosed by the invention is applied on a machine tool and realizes drilling and milling processing of workpieces under the condition of once clamping, so that the accuracy of shapes and positions of holes or key grooves is ensured and the environment-friendly and energy-saving effects are achieved.