This invention belongs to a machinery for mechanically removing stamens of corns in the operation of planting corn, specifically to a self-propelled over-partition type corn detasseling machine, comprising a hydraulic pump and a hydraulic control system, which are driven by an engine, disposed on a carriage equipped with wheels; a steering wheel and a hydraulic steering gear are further arranged on the carriage; a steering hydraulic cylinder mounted on the carriage controls the turning of front wheels by a connecting bar and a crank; front and rear wheels are mounted respectively in the lower portions of the front and rear crossbars of the carriage by supporting arms, and are respectively driven by a hydraulic motor; and a four-bar mechanism equally hinged with the supporting arms is arranged in the front portion of the carriage, which is controlled to rise or descend by the hydraulic cylinder; a detasseling device driven by the hydraulic motor is arranged on the front bracket of the four-bar mechanism. The invention replaces manual detasseling with mechanical operation with high working efficiency; the machine reduces agro-industrial labour intensity and cost for detasseling per area, besides, the invention can enlarge the production scale of corn seed production and prompt the industrialization of corn seed production.