In order to explore the effect of the mix with a high ratio of potato flour and wheat flour on noodle processing and quality evaluation, the modified potato flour, which was pre-prepared with soybean protein isolate adding and ultrasonic treatment, was used as the research target. The steady-state rheological properties of the mix with different proportions of potato flour and wheat flour, tensile properties, texture properties and sensory evaluation of steamed noodles were measured for a comprehensive evaluation. The results showed that when the proportion of potato flour reached 50%, the apparent viscosity showed the most stable with the shear rate, and the flow index value was higher than that of the other ratios. This was close to the Newtonian fluid, indicating that the addition of potato flour can reduce the flow resistance and facilitate the processing of products. The effect of ultrasonic treatment combining with soybean protein isolate played a positive role in improving the ductility, plasticity, strength and strength of raw potato flour. The texture characteristics and quality of cooked noodles of modified potato flour were generally positively reviewed. Its chewiness is lower than that of wheat flour noodles, which can provide people with a better chewing experience. It has been proved that the ratio of modified potato flour mixed with wheat flour could be increased after modifying treatment, which was beneficial to the promotion of potato being used for staple food grain.