Abstract: Detecting the main tractor noise source is the most important condition to solve the problem of tractor noise. Sound intensity can be used todetect noise source of tractor effectively. A noise signal test system of ShenniuSN250 tractor was established based on virtual instrument LabVIEW, which can measure the noise signal of tractor and carry on the noise spectrum analysis and the noise source recognition by using the sound intensity method to analyze themain noise source of the tractor. The results indicate that the established test system meet the requirement of engineering precision and can distinguish main tractor noise source effectively. The exhaust noise, the engine ventilator noise and the noise of vibrating cover of the engine are the main noise source of the tractor, and the levels of sound intensity are 106 dB, 104 dB, and 104 dB respectively. The exhaust noise is the main source of the cab. Therefore, in order to solve the problem of the tractor noise, the exhaust noise, the engine ventilator noise and the noise of vibrating cover of the engine should be reduced first.