The invention discloses an octagonal cable protection pipe and a preparation method thereof and belongs to the technical fields of compounding and preparation methods of compounds. The octagonal cable protection pipe comprises, by weight, 100 parts of PVC (polyvinyl chloride), 25-35 parts of filler, 15-20 parts of active nano-calcium carbonate, 3-3.5 parts of stabilizer, 3.2-4.2 parts of lubricant, 6-10 parts of impact modifier and 0.4-0.8 part of toner, wherein the lubricant consists of paraffin and stearic acid which are in a weight ratio of 0.7 to 3. The octagonal cable protection pipe has the advantages that mainly prepared from the PVC resin, the octagonal cable protection pipe subjected to extrusion molding under a high pressure and at a high temperature is highly resistant to impact, high temperature, cold, flame and wear, long in service life and excellent in insulativity and keeps a certain flexibility, and can play a protective role in communication optical cables and cables when used for laying underground communication pipelines.