The invention relates to a cloth cutting structure of fabric stretcher that includes left wall board, right wall board, nose girder, cloth sliding board, cutting head guide rail, cutting head, synchronous belt driving device, synchronous belt, moment motor, arm pressing axis, a set of pressing arm, hold down strip, a pair of travel switch, spring holder, a pair of pothook, spring and electrical switch, a assistant take-off roller, a wind pipe and air generating device. The using of assistant take-off roller makes the cloth smoothly guide to cloth sliding board, and the using of wind pipe and air generating device make the cloth sliding board form air film that is benefit for the normalization of the running of fabric stretcher.