The invention relates to a detection device capable of determining the flow capacity of a volute flow channel. In a turbocharger, waste gas exhausted by an engine is used for pushing a turbine in a volute to rotate to drive a gas compression impeller to do work; the flow capacity of a volute flow channel directly influences the rotating speed of the turbine, wherein residues such as a sand core are extremely likely to exist in a volute flow channel in the volute in the casting process, and the flow capacity is influenced; there is not an effective method for detection all the time. According to the device, the capability of inputting compressed air from the air inlet vertical wall to push the turbine when the working state of the volute is simulated is adopted, and the lower limit of the revolution is set to be a qualified value according to the revolution of the turbine pushed to rotate by air with certain pressure; the circulation capability of the volute is detected through instruments such as an inductor counter.