The utility model discloses a harvester granary unloads grain clutching mechanism, including sunshade support, rotary draw rod, bent plate, connecting rod, tensioning arm seat, tensioning arm, the tensioning arm is installed on the tensioning arm seat, rotary draw rod installs on the back shaft of sunshade support, and the bent plate upper end is connected with rotary draw rod, and the bent plate lower extreme is connected with the small end, and the tensioning arm is connected to the connecting rod lower extreme. The utility model provides an unreliable fragile problem of flexible axle, can also unload the grain condition by in situ observation when unloading grain.