Drilling is one of the complex machining ways. The object of this investigation was to study cutting deformation in drilling by finite element method. A finite element model was developed to study the cutting deformation in drilling with various feed rates and various drilling velocities based on equivalent model. Experimental study on the cutting deformation in drilling was also carried out by a drilling quick-stop device. It is indicated that cutting deformation decreases when the drilling velocity and the feed rate increase; the closer the distance to the web is, the smaller the cutting deformation is; the laws of cutting deformation obtained from finite element method are according to that obtained from experiment.