and driven by the conveying mechanism 20 to move on the work platform 10 to a position below the sewing head 41 or the processing head 51 the positioning mechanism 103 the conveying mechanism 20 the clamping device 201 and the processing device 50 are electrically connected to the computer controlled sewing machine 40 and controlled to operate by the processing program the processing program controls the positioning mechanism 103 to fix the fixing mechanism 30 to the work platform 10 and make the clamping device 201 selectively clamp the first positioning part 33 or the second positioning part 34 and the fixing mechanism 30 is driven by the conveying mechanism 20 to move on the work platform 10 the processing program can calculate the accurate movement distance of the fixing mechanism 30 between the sewing head 41 or the processing head 51 by using the positioning distance and the relative distance in this embodiment the positioning distance between the first and second positioning parts 33 34 of the fixing mechanism 30 is equal to the relative distance between the processing head 51 of the processing device 50 and the sewing head 41 of the computer controlled sewing machine 40 so that position coordinates can be obtained to move the fixing mechanism 30 between the sewing head 41 and the processing head 51 what mentioned above are the structure relations of the main components of the embodiment for a better understanding of the function and operation of the present invention reference should be made to the following description when taken into conjunction with fig1 to 4 4 the positioning method of the computer controlled sewing machine positioning system in accordance with the present invention.