The invention relates to the technical field of oil-gas separator production and machining accessory devices, in particular to an oil-gas separator filter element cutting device. A filter material fixing effect is improved, the cutting accuracy is guaranteed, and the practicability is enhanced; and moreover, the potential safety hazard is reduced and the reliability in use is enhanced; and meanwhile, the filter material can be rapidly positioned so that the cutting efficiency is enhanced. The oil-gas separator filter element cutting device comprises a cutting platform, a cutting bracket, a cutting cylinder, a piston rod, a mounting plate, a cutting knife, a driving motor, a front supporting plate, a rear supporting plate and a conveying plate; a transverse conveying groove is formed in thetop end of the cutting platform; the conveying plate is positioned in the conveying groove; multiple groups of supporting springs are arranged at the bottom end of the conveying plate; multiple groups of conveying wheels are arranged on the conveying plate in an unequally-spaced manner; a driving wheel is arranged between the front supporting plate and the rear supporting plate; the oil-gas separator filter element cutting device further comprises a positioning device and a controller; a cutting groove is formed in the top end of the cutting platform; and the positioning device comprises a fixing plate, a threaded rod, a threaded tube, a supporting plate, a push plate, a pressure sensor and a ball bearing.