The invention relates to a fast assembly and disassembly mechanism for nonlinear large-aperture optical elements, which solves the problems that the time for on-line exchange and assembly debugging is long and the efficiency is low in the traditional nonlinear large-aperture optical elements. Roller mounting holes are arranged in a supporting frame, roller guide columns are arranged in the roller mounting holes, roller shafts are arranged on the roller guide columns and are provided with rollers, locking sheets are arranged on the supporting frame through locking sheet press blocks, mounting base plates are arranged on the regulating frames, baffles are arranged on the base plates, locking head shells are arranged on the base plates, the base plates, the locking head shells and locking blocks are connected by locking pins, the regulating frame is provided with a locating block, a locating bolt is arranged in the locating block, the rollers are connected with the regulating frame, the base plates and the baffles, the supporting frame is connected with the locating bolt, the locking sheets are inserted between the locking blocks, and locking bolts are connected with the locking blocks. The fast assembly and disassembly mechanism disclosed by the invention is applied to on-line exchange and assembly debugging experiments of the nonlinear large-aperture optical elements.