The invention discloses a divider fixing device for a harvester. The divider fixing device for the harvester is characterized by comprising a platy fixing baffle; a driving hydraulic cylinder is arranged at the tail of the fixing baffle, an adjusting shaft arm is arranged at the head of the driving hydraulic cylinder, a fixing round hole array formed by fixing round holes is formed in the fixing baffle, two detachable fixing clamping blocks are arranged on the two sides of the fixing baffle respectively, and a supporting frame is arranged between the tops of the fixing clamping blocks. In the use process, once the adjusting shaft arm is damaged, a user only needs to detach the fixing clamping blocks on the two sides of the fixing baffle and the supporting frame on the fixing clamping blocks, and thus the divider fixing device for the harvester is easy and convenient to use, easy to operate and especially suitable for field maintenance in farmland.