The invention relates to the technical field of equipment for producing light diffusion plates, in particular to a co-rotating twin-screw compound extruder for producing light diffusion plates and a production process thereof. The co-rotating twin-screw compound extruder mainly consists of a frame, a feeing device, a transmission device and an extruding device, wherein the extruding device mainly consists of a feeding section, a melting section and a homogenizing section; the melting section mainly consists of interrupted screw edges and annularly arranged pins; vacuumizing exhaust devices are respectively arranged at the upper and lower ends of the melting section; and multiple discharge holes are formed on screw edges of twin screws in the extruding device in the axial direction of the screws. After the structure is adopted, the melting section consisting of the interrupted screw edges and the annularly arranged pins can be used for fully plasticizing materials; the holes formed in the axial direction of the screw edges are used for making up the defect of extruding out broken materials in the movement engagement process of the twin screws in the extruding process so as to realize continuous and stable material extruding process; and the upper and lower vacuumizing exhaust devices are used for discharging impurities and waste gas to guarantee the quality of the light diffusion plates.