In order to solve the problems of serious grain breakage and high unstripping rate in the direct harvest of corn in doublecropping area, a longitudinal axial flexible hammerclaw corn threshing device was designed. The threshing device adopted the longitudinal axial flow threshing drum, and the threshing hammerclaw was installed on the threshing drum. Different types of threshing hammerclaw can be replaced in the front and back sections of threshing, and the threshing hammerclaw can be flexibly connected with the threshing drum to reduce the grain crushing rate and realize the flexible and lowdamage threshing of corn. The threshing concave plate adopted a segmented combination type, which was convenient for the adjustment of the threshing section and the separation section. The concave plate cylindrical steel was designed with a semispherical protrusion to increase the rubbing force and improve the removed rate. The feeding amount and drum rotational speed, threshing hammerclaw type were taken as test factors, the orthogonal experiment under different moisture contents was confirmed, roller speed and the best parameter combination of threshing hammerclaw results showed that under the condition of moisture content of 25.12%, the best parameter combination for the drum rotating speed was 500r/min, feeding amount was 8kg/s, the takeoff section was a flat head threshing hammer, and the flat and strong release sections were round head threshing hammerclaw, the grain crushing rate was 3.73%, unstripping rate was 0.69%. Under the condition of water content of 32.83%, the optimal parameter combination was the drum speed of 450r/min, the feeding amount of 8kg/s, the takeoff section, the flat and strong release sections were all round head threshing hammerclaws, and the grain crushing rate and unstripping rate were 4.36% and 0.70%, respectively. 