The invention discloses a PC (
Polycarbonate) material with an excellent transparent light 
diffusion function and a preparation method thereof. The PC material is composed of 
polycarbonate, 
flame retardant 
masterbatch, an auxiliary 
flame retardant, a compound light diffuser, an 
antioxidant, a 
flame retardant synergist, a 
lubricant and other auxiliaries. The principle ingredient of the PC material is PC resin; the PC material is extruded by two steps, wherein the first step is to blend a 
sulfonate type major flame retardant and an organic 
silicon flame retardant with the PC resin by melting and granulate the mixture through 
extrusion by virtue of a twin-screw extruder so as to obtain the light diffusible flame retardant 
masterbatch, and the second step is to add the compound light diffuser, the flame retardant 
masterbatch, the 
antioxidant, the flame retardant synergist, the 
lubricant and other auxiliaries for further melting blending by taking PC as the major ingredient, and then extrude and granulate the mixture. The flame-retardant light diffusible PC material provided by the invention can be widely applied to an LED (Light-Emitting 
Diode) lamp, the backlight of a 
liquid crystal display, a transmission type screen, a decorative lighting billboard, an advertisement lamp box and the like in the lighting field.