The invention relates to a corrugated tube material and particularly discloses a flame-retardant PP (Polypropylene) / nylon corrugated tube composite material and a preparation method thereof, aiming to overcome the shortcomings in the prior art that the mechanical property of the PP corrugated tube is bad, the nylon corrugated tube is not flame-retardant, the stability is bad, and the service lifeis short. The material disclosed by the invention comprises the following substances by weight percentage: 47-75 of PP, 3-40 of nylon, 5-30 of flame retardant, 5-20 of compatilizer, 1-40 of flexibilizer, 0-10 of filling master batches, 0.2-1.5 of heat stabilizer, and 0.2-1.5 of processing agent. The preparation method comprises the steps as follows: the filling master batches are firstly preparedand then added into a twin-screw extruder to melt and mix with other materials, and pelletings are extruded out to prepare the flame-retardant PP / nylon composite material. The invention has the advantages of favorable flame-retardant property, excellent high-temperature resistance, friction resistance, chemical corrosion resistance, long service life, high surface glossiness, high electrical insulativity, simple manufacturing technology, and low cost.