A new design method of spiral structure with equal diameter and variable pitch is proposed to improve the spiral feeding accuracy of wheat flour. Solidworks software is used to establish a three-dimensional model and the wheat flour material is used for discrete element simulation to observe the feeding amount and feed opening of the spiral feed section. The stability of the flow rate is compared with the conventional equal-diameter variable pitch spiral structure. The tests shows that, compared with the existing equidistant spiral structure, the experimental design of the variable pitch spiral feed section is uniformly fed at the same speed and outer diameter, with the spiral feed flow rate of 0.224 kg/s, the flow fluctuation ranging from 0.207 to 0.239 kg/s, and the fluctuation percentage within ±6.69%. Under the premise of meeting the design requirements, its accuracy is higher than that of the conventional equidistant spiral.