The invention discloses a 
threshing cleaning device of a longitudinal-axial-flow 
combine harvester, and belongs to the technical field of combine harvesters. The 
threshing cleaning device comprises a 
threshing separating device, a cleaning device body and a stalk 
chopper. The threshing separating device comprises a 
threshing machine body and a longitudinal-axial-flow roller driven by a power device. The longitudinal-axial-flow roller comprises a feeding-in part and a roller body part, and the roller body part sequentially comprises a threshing section, a separating section and a 
weed-discharging section. A feeding-in shell is fixed to the portion, corresponding to the feeding-in part, of the 
threshing machine body, a threshing section roller cover is arranged on the upper portion, corresponding to the threshing section, of the 
threshing machine body, and a threshing section concave plate is arranged on the lower portion, corresponding to the threshing section, of the threshing 
machine body. A separating section roller cover is arranged on the upper portion, corresponding to the separating section, of the threshing 
machine body, a separating section concave plate is arranged on the lower portion, corresponding to the separating section, of the threshing 
machine body, and the 
diameter of the separating section roller cover is larger than that of the threshing section roller cover. The feed quantity is large in harvesting, the function of returning stalks to the field is achieved, working efficiency is improved, kinds of crops are harvested, and the requirements for earnings of a user are met.