Abstract: According to the defect of vehicle fuel consumption directly testing method and the current problems existing in the carbon balance method, intelligent testing method for vehicle fuel consumption was studied based on virtual instrument technology, which including sampling system, flow sensor and emission analyzer. The vehicle fuel consumption calculation model suitable for China's specific condition was established based on carbon balance method, and fuel consumption test system was designed according to the test system function requirements. Through the experiments, comparison with fuel consumption meter test results for the real car was conducted based on the data processing analysis. The fuel consumption mathematic calculation model was modified through the curve fitting and linear regression,. The consumption sampling testing system is convenient to collect samples, and can satisfy the various testing conditions with a precision of 3.5%. It can realize fast inspection of vehicle fuel consumption without disassembly testing.