The invention discloses a device and method for determining the gas cut type in the drilling process. The device comprises an outlet flow detection device, an inlet flow detection device and a controller, wherein the outlet flow detection device is used for detecting the flow of drilling fluid at an outlet; the inlet flow detection device is used for detecting the flow of drilling fluid at an inlet; the controller is used for having control over increase of back pressure on a shaft when gas cut happens and determining the gas cut type according to the flow of drilling fluid at the outlet and the flow of drilling fluid at the inlet after back pressure is increased for a period of time. According to the device and method for determining the gas cut type in the drilling process, after back pressure on the shaft is increased for a period of time, the gas cut type is determined according to the flow of drilling fluid at the outlet and the flow of drilling fluid at the inlet, the mode and the shaft pressure control process can be performed in parallel, the shaft bottom gas inlet type is judged while the pressure of the shaft is controlled to be stable, and thus not only can a gas cut control scheme be accurately made, but also the safety degree of pressure control drilling is greatly improved.