Abstract： Taking a combine harvester as research object, based on the sound intensity test technology, the surface acoustic intensity of the harvester was tested by pp method. According to the sound intensity distribution results of each test surface, the main noise sources of the harvester were analyzed and identified. The test results show that when the harvesting machine cutting, threshing, cleaning and other operating mechanisms stop working (that is, when the combine harvester is not in operation), the main noise source of each test surface is from the engine. When the cutting, threshing, cleaning and other operating institutions work normally (that is, when the harvester is under working condition), the main noise sources of each test surface are different. The front noise source is mainly from the engine, the header device and the intermediate conveying device，while the back end noise source is mainly from the threshing device, the cleaning device and the engine exhaust system. The left side noise source is mainly from the header device and the threshing device，and the right side noise source is mainly from the engine and header device.
