The invention relates to the technical field of rope processing, in particular to a polypropylene rope fixed-length cutting-off processing device. The device comprises a rope pulling assembly, a clamping assembly, second electric cylinders, second supporting columns, first electric cylinders, first blades and second blades. A polypropylene rope is pulled downwards through the rope pulling assembly, when the polypropylene rope moves downwards to a proper position, the bottom of the polypropylene rope is fixed through the clamping assembly, the second electric cylinders work to drive the secondsupporting columns to move leftwards, the first electric cylinders work to drive first supporting columns to move rightwards, the polypropylene rope is pulled to move downwards through the moving second supporting columns and the moving first supporting columns, the second supporting columns and the first supporting columns support the polypropylene rope, and when the first supporting columns andthe second supporting columns move to make contact with the first blades and the second blades respectively, a plurality of fixed-length polypropylene rope segments are cut at a time, so that the working efficiency is improved; and manual work is replaced with a machine, so that time and labor are saved.