The invention relates to a mould cutting device for a computer pattern sewing machine. The mould cutting device mainly comprises an adjusting base, a lifting shaft, a gear shaft, a high speed electronic grinding machine and an electronic grinding machine fixing set, wherein three through holes are formed in the adjusting base and are respectively connected with the gear shaft, a connection rod and the lifting shaft, tooth lines are arranged at the upper section part of the lifting shaft, one end of the gear shaft is connected with a hand wheel, the other end of the gear shaft is connected with a gear, the gear is arranged in the adjusting base and is clamped with the tooth lines of the lifting shaft, a milling cutter is arranged at the lower end of the high speed electronic grinding machine, and one side of the electronic grinding machine fixing set is connected to the lifting shaft. The mould cutting device for the computer pattern sewing machine is characterized in that the hand wheel drives the lifting shaft to vertically move through the gear shaft, so that the lifting shaft drives the high speed electronic grinding machine to vertically move. The hand wheel rotates to enable the milling cutter to vertically move and machine a machined plate, and the structure is simple and practical in structure and convenient to operate.