Abstract: As one of the main local characteristic food in the northwest China，potato yuyu was very popular among the people for its rich nutrition，and effectively promoted the development of potato consumption.In order to overcome problems of low production efficiency，high labor intensity and inconsistent product specifications of traditional hand-made potato yuyu，structure of potato yuyu molding machine was optimized and related performance test of potato yuyu molding machine was carried out by studying forming mechanism of potato yuyu.Results showed that molding angle was an important structural parameter which affected molding effect.Molding speed of potato yuyu was positively correlated with molding rate within a certain range，the molding rate would decline when molding speed of potato yuyu exceeded a certain range.Stiffness and positioning orientation of molding roll affected molding effect of potato yuyu.