The invention discloses a preparation method of UV (ultraviolet)-curable low-oxygen-polymerization-inhibition nano hybrid filler. The method comprises steps as follows: an aminosilane coupling agent and multifunctional acrylic glycidol are taken, the temperature is adjusted to range from 40 DEG C to 70 DEG C for a reaction, a first-step target product is obtained, multifunctional isocyanate, a polymerization inhibitor and a catalyst are added to the first-step target product, the temperature is adjusted to range from 50 DEG C to 80 DEG C for a continuous reaction, a second-step target product is obtained, a polymerization inhibitor, a catalyst and a photoinitiator are added to the second-step target product, the temperature is adjusted to range from 80 DEG C to 100 DEG C for a continuous reaction, a third-step target product is obtained, a mixed solvent containing functional silane is added to the third-step target product, the temperature is adjusted to range from 25 DEG C to 60 DEG C for hydrolysis under the slightly alkaline condition and under the ultrasonic effect, a product after hydrolysis is dried, and the UV-curable low-oxygen-polymerization-inhibition nano hybrid filler is obtained. The method adopts the simple technology and is easy to control, and the prepared product can relieve oxygen polymerization inhibition and increase the UV-curing speed.