The invention discloses photodiffusion particles. The photodiffusion particles comprise, in parts by weight, 100 parts of organic trialkoxysilane monomers and 1-10 parts of inorganic particles. A preparation method of the photodiffusion particles comprises steps as follows: the inorganic particles are dispersed in an aqueous solution containing a dispersant and stirred for 20-40 min by a stirrer, the pH value is adjusted to 4.5-5.0, the organic trialkoxysilane monomers are added, the mixture is mixed, hydrolysate is obtained and continuously stirred for 20-40 min by the stirrer, the pH value of the hydrolysate is adjusted to 8.5-9.0, the hydrolysate reacts for 3-5 h and then is filtered, cleaned and dried, and the photodiffusion particles are obtained. According to the prepared photodiffusion particles, inorganic particles in small sizes are wrapped with organosilicon photodiffusion particles in large sizes, so that light rays can produce reflection on the surfaces of the inorganic particles to a certain extent when passing through the organosilicon photodiffusion particles, the light rays are scattered in a wider range, and the shielding effect and the haze of the material are improved while the light transmittance of the thermoplastic photodiffusion material comprising the photodiffusion particles is guaranteed.