The invention discloses a low-expansion-coefficient nylon heat-insulating strip master batch. The master batch is prepared from nylon 66 resin, alkali-free glass fibers, an antioxidant, calcium sulfate whiskers, black master batch and inorganic filler according to the mass ratio of 50 to 25 to 0.8 to 11.5 to 0.7 to 12. The invention also discloses a processing method of the master batch. The processing method comprises the following steps of step 1, preparing raw materials; step 2, premixing the raw materials; step 3, melting the raw materials and granulating; step 4, screening; and step 5, cleaning and drying. The master batch can be screened, cleaned, dried in a same device, labor consumption and energy consumption are effectively reduced, movement of multiple devices of the master batchis avoided, abrasion damage to the master batch is reduced, the quality of the master batch is better, nylon 66 resin is adopted as a raw material of the master batch, the master batch has the characteristics of high mechanical strength, high melting point and the like, so that the melt-extruded master batch has the advantages of low expansion coefficient, high heat resistance, high strength, high toughness and the like.