The work aims to design the structure of mixing paddle to make the mixing effect faster and more uniform in view of the machinery equipment for quantitative filling of two viscous liquid materials after mixing. The finite element method was used to analyze the three-dimensional flow field characteristics of the fluid materials filled into the mixer and study the effects of different mixing paddles on the pushing, mixing and filling of the corresponding materials. Then, the continuous speed field, pressure field and mixing effect under various working conditions were compared. The stirring motion of the paddle made the materials mix quickly and evenly in a short time. The axially staggered forward-inclined propelling paddle not only mixed the fluid, but also increased the transport capacity and reduced fluid internal pressure, which reduced the complexity of process and structural design. An effective method for predicting the optimal design result of stirring paddle is obtained. The research results provide a theoretical basis and reference for the upgrading of small viscous material filling and mixing machine.