The invention discloses master batch of a high-transmittance and high-masking diffusion plate, a method for manufacturing the master batch and a method for manufacturing the diffusion plate. The master batch comprises, by weight, 100 parts of polystyrene, 10-11 parts of organic silicon resin, 0.3-0.4 part of titanium dioxide powder with the particle size of 2-5 micrometers, 0.15-0.2 part of fluorescent brighteners and 0.02-0.025 part of mineral oil. The polystyrene, the organic silicon resin, the titanium dioxide powder, the fluorescent brighteners and the mineral oil are blended with one another and then are squeezed to obtain the master batch, 6.1 parts of the master batch and 100 parts of polystyrene are blended with one another and then are squeezed to obtain mixtures, and the mixtures are further impressed and shaped to obtain the high-transmittance and high-masking diffusion plate. The master batch and the methods have the advantages that the purpose of plastically modifying the master batch mainly can be achieved by diffusion particles by the aid of auxiliary chemical raw materials for color increasing and toughening, accordingly, the diffusion plate has a diffusion function, high-masking effects further can be realized, the transmittance of the diffusion plate can reach 65+ / -3%, the haze of the diffusion plate can reach 99%, and the diffusion of the diffusion plate can reach 88+ / -5%; the cost of modules further can be reduced while requirements on light weights and thinness of the backlight modules are met.