针对结构单一的普通单螺杆混合性能和剪切性能较差这一问题，在普通单螺杆的基础上改变螺纹头数和螺杆底径，提出一种新的渐变式单螺杆结构。采用SolidWorks建立渐变式单螺杆和普通双头单螺杆两种模型，依据有限元法（FEM）利用Ansys对两种模型进行仿真并分析，得到的压力、剪切速率和停留时间等结果，评估渐变式单螺杆的性能。结果表明：渐变式单螺杆流场内的压力峰值约为普通双头单螺杆的4.7倍，拥有更强的建压能力；渐变的螺杆底径使流场内的剪切速率增大，拥有更好的剪切性能；渐变式螺杆螺纹头数的增加使流场内物料停留时间延长，是普通双头单螺杆的2.3倍，物料混合更均匀，渐变式单螺杆拥有更强的混合性能。研究为单螺杆挤出机结构的优化和性能的提升提供依据。

Aiming at the problem that the conventional single-screw has poor mixing and shearing performance due to its simple structure, a new graded single-screw structure was proposed by changing the number of threads and the root diameter of the screw based on the conventional single-screw. Using SolidWorks, models of the progressive single-screw and the conventional twin-headed single-screw were established. Based on the Finite Element Method (FEM), the two models were simulated and analyzed using Ansys. The results, such as pressure, shear rate, and residence time, were used to evaluate the performance of the graded single-screw. The results showed that the pressure peak within the flow field of the graded single-screw was approximately 4.7 times that of the conventional twin-headed single-screw, indicating a stronger pressure-building capability. The varying root diameter of the screw increased the shear rate in the flow field, resulting in better shearing performance. The increase in the number of threads of the progressive screw extended the residence time of the material in the flow field to 2.3 times that of the conventional twin-headed single-screw, leading to more uniform mixing of the material. The graded single-screw thus exhibited superior mixing performance. The study provides a basis for the optimization of the structure and improvement of the performance of single-screw extruders.