The invention discloses a drilling and milling cutter which is used for conducting drilling and milling machining and vertical sampling on a machined surface. The drilling and milling cutter comprisesa cone-shaped cutter head (1) and a plurality of blades (2). The middle of the cutter head (1) is provided with a sampling hole (6) penetrating through the cutter head (1) and a plurality of grooves(5) formed around the sampling hole (6). The multiple blades (2) are adjustably arranged in the multiple grooves (5) correspondingly, and the blades mutually form included angles and form gaps in thesampling hole (6), so that when the cutter conducts drilling and milling to form chamfers, machined materials are sampled in the sampling hole (6) through the sampling gaps. Thus, sampling and chamfering are completed simultaneously in the process of ingot sampling, and chamfering work during lathe sampling is effectively avoided.