In order to accurately test the fuel consumption with carbon balance method, a series of characteristic studies were carried out on V-cone flowmeters for exhaust flow measurement. The Fluent was used to simulate the flow of V-cone flowmeter, and the influence of key factors on the permanent pressure loss and discharge coefficient such as different values of equivalent diameter ratio, fore-and-aft V-cone and Reynolds number etc. were studied. Then, two V-cone flowmeters were designed and comparison experiment with Venturi tubes was carried out . Finally, two fitting formulas which were deduced from the Venturi tubes’test were used as calculation models. The result of the experiment indicates that the simulation and the experiment have strong consistency and the flowmeters are of great accuracy and stability, and they can be used to measure the vehicle exhaust gas flow. 