The invention provides a barrier board structure of a folding machine. The structure comprises a barrier board, a paper guide, a belt and an adjusting device; the barrier board is provided with a sliding groove, the paper guide is mounted on the barrier board, a paper blocking piece is arranged at the front end of the paper guide, and is inserted in the sliding groove, the adjusting device is mounted at the opposite end of a paper inlet of the barrier board, the belt can drive the paper guide to move in the direction of the sliding groove, and the adjusting device comprises a combing shaft, a transmission adjusting assembly and a driven adjusting assembly; the transmission adjusting assembly comprises a first fixed base, a casing shaft is embedded on the first fixed base, a transmission wheel and a parallel adjusting hand wheel are arranged on the casing shaft, a turbine is arranged between the transmission wheel and the parallel adjusting hand wheel, a transverse moving adjusting hand wheel is arranged at one end of the combing shaft, a first screw and a second screw are axially arranged on the end face of the transverse moving adjusting hand wheel, and a worm is arranged on the fixed base; transverse moving of the paper guide can be adjusted through the adjusting device, the adjusting speed of the paper guide is higher, the adjusting precision of the paper guide is higher, and the production efficiency is improved.