Abstract: In order to study the effects of different threshing components on threshing and separating performance, a test of grain threshing and separating performance was carried out by using the rectangular tooth, short-rasp-bar, spike tooth, cutter tooth and trapezoidal tooth. The threshing and separating indexes, such as power, losing rate, impurity rate, primary threshing-separating rate, distribution of mixture along the axial and cylinder radial of the tangential-axial test device, were compared with the different threshing components under grain feed rate of 7 and 8 kg/s. Result showed that primary threshing-separating rate of the tangential flowing test-device with cutter tooth was 47.71%, and loss rate of axial flowing test-device was 0.25% at the grain feed rate of 7 kg/s. Unit power consumption, the loss rate and the completely threshing rate were 8.51 kW/(kg·s), 0.31%, and 99.96% respectively with the cutter tooth tangential flowing test-device and the spike tooth axial flowing test-device at the grain feed rate of 8 kg/s.