To explain the phenomenon of poor separation effect of powder separator in the process of collecting powdered sugar, simulation analysis of powder separator was made with using Fluent software. Based on the existing structure, changing the outlet structure, increasing the height, reducing the diameter of the separator and installing spiral guide vane respectively, to make comparison of the effects of different structures of separator. In addition, the influence of air intake mode is discussed. Weak separation capacity close to separator outlet section leads to powder splash; Equipped with spiral vanes is more conducive to improve the separation capacity than other separator structure; Air intake mode has some influence on separation effect, using imported air way contributes to separation effect than export suction air way, but air intake mode has less effect on the separation ability of sugar powder separator; Sugar powder separator with spiral guide vane is more suitable for collection and separation of sugar.