The invention discloses high-temperature oil-resistant and flame-retardant chlorinated polyethylene heat-shrinkable tubing as well as a preparation method and an application thereof. The heat-shrinkable tubing comprises the following components: chlorinated polyethylene, resin A, resin B, a polymer compatibilizer, black masterbatch, antimonous oxide, a flame retardant synergist, a halogen-free flame retardant, a thermal stabilizer, hydrotalcite, an antioxidant, a sensitizer and a silicone additive. The method comprises the following steps: firstly, banburying the antimonous oxide, the flame retardant synergist, the halogen-free flame retardant and hydrotalcite; adding and banburying the chlorinated polyethylene, the resin A, the resin B, the polymer compatibilizer, the black masterbatch, the thermal stabilizer, the antioxidant and the silicone additive; finally adding a sensitizer and banburying, and then palatalizing, and extruding to form the tubing; and carrying out irradiation crosslinking, expanding drawing, cooling sizing, and marking, so as to obtain the high-temperature oil-resistant and flame-retardant chlorinated polyethylene heat-shrinkable tubing. The high-temperature oil-resistant and flame-retardant chlorinated polyethylene heat-shrinkable tubing has the advantages of being low in price, efficient, flame-retardant, excellent in mechanical property, low in pollution, high in high-temperature oil resistance, and good in resistance to acid and alkali corrosion, and can be applied to a bad working condition.