The invention discloses a master batch with a light scattering function, and a preparation method and application thereof. The master batch with a light scattering function comprises 20-99.5% of transparent thermoplastic resin, 0.1-40% of small-particle-size light scattering agent, 0.1-10% of large-particle-size light scattering agent, 0.01-10% of antioxidant and 0.01-20% of light stabilizer. By compounding the light scattering agents with two particle sizes, the optical properties of the light scattering material can be obviously enhanced. Under the condition of the same content of light scattering agent, since the light scattering agents with two particle sizes are compounded, the light scattering material not only can achieve the same light scattering effect, but also has better light transmittance. The light scattering agents, antioxidant, light stabilizer and other functional assistants are mixed with the matrix resin to prepare the functional master batch, so that the concentration of the assistants in the master batch is increased; and the functional master batch is blended with the matrix resin to prepare the light scattering material. The invention has the advantages of low consumption of light scattering agents, uniform distribution, excellent optical properties, fewer surface defects, lower cost and the like. The master batch with a light scattering function is suitable for producing high-quality optical components, lamp shells, diffuser plates in backlight modules, advertisement signboards, display windows and the like.