The invention discloses a preparation method of an antifogging and antireflection film coating liquid. The preparation method comprises the following steps: (1) dispersing nano silica in deionized water to prepare a dispersion liquid with mass percent concentration of 0.1-30%, adding a silane coupling agent to the dispersion liquid, heating to raise the temperature, and reacting for 0.2-1 hour; (2) adding a mixed solution which is formed by acrylic acids and acrylic esters and is diluted by a diluent to the solution in the step (1), stirring and mixing the solutions at 50-80 DEG C for 30-40 minutes, then adding an initiator, reacting for 5-10 hours, and cooling to obtain a nanocomposite dispersion liquid; (3) diluting the nanocomposite dispersion liquid in the step (2) into a solution with concentration of 0.1-50wt%. The preparation method has the beneficial effects that an in-situ free radical polymerization method is adopted, the coating effects are better, the coating can be ensured to have good apparent properties, and the coating is high in drying speed and has excellent antireflection and anti-dazzle effects.