The invention discloses a cutting mechanism which is used for a steel cutting device and is convenient to disassemble and maintain. The cutting mechanism comprises a cutting device base, a cutting platform is fixedly connected to the upper end face of the cutting device base through supporting columns which are symmetrically arranged, and an MAM-200 controller is installed on the cutting platformand electrically connected with a power supply; steel clamping devices are symmetrically and detachably installed at the two ends, close to the edges, of the cutting platform; two groups of electric sliding ways driven by a brushless direct-current servo motor are symmetrically arranged between the two groups of steel clamping devices about the central line of the cutting platform; the brushless direct-current servo motor is electrically connected with the MAM-200 controller; and the lower segments of the electric sliding ways are detachably installed on the cutting platform through electric sliding way fixing parts. According to the cutting mechanism, all key cutting mechanisms and cutting auxiliary mechanisms can be steadily connected with the cutting device or safely disassembled from the cutting device, and the effect that disassembling, transporting and installing are all convenient is achieved.