Abstract: This paper explores a full-mesh triangular prism mixing element for twin-screw extruders to solve the production process problem of new glass fiber reinforced materials, explains its full meshing design theory, and proposed an eccentric design method which makes the component have better mixing effect and better interchangeability, and it is clear that the range of eccentricity and screw radius is 0~0.423. Then the geometric properties of the components are analyzed in detail according to the geometric principle. The expressions of the design parameters and the volume of the mixing cavity are derived. The numerical fitting method is used to simplify the expression to be applied to the actual design. Finally, the analysis of mixed surface normal shows the relationship between the conveying capacity and the component spiral parameters, and gives that the reasonable range of parameter selection is 2~8 which can not only maintain good mixing effect, but also have better conveying capacity. The necessary theoretical preparations are provided for the design and manufacture of the component and the hybrid experiment.