The invention discloses a high-temperature-resisting, insulating and inflaming-retarding power cable material and a preparing method thereof. The material is prepared from, by mass, polyolefin elastomer, nano-zirconia, glass fiber, PBO fiber, polyimide fiber, polypropylene, pentaerythritol tetrakis(2-mercaptoacetate), trioctylphosphine orthophthalic triformate, polybutylene terephthalate, cyclohexanedicarboxylic acid diglycidyl ester and toluene diisocyanate. The power cable material is high in bending strength, bending modulus, tensile strength, weather resistance and high temperature resistance, the influence of the environment on a cable sheath is reduced, strength is high, hardness is high, impact resistance is high, stability is excellent, service life is long, corrosion resistance, fire retardancy and insulating property are realized, and the material is worth application and popularization in multiple fields.