Using three different crystal forms of starch， namely rice starch (type A)， potato starch (type B)， and pea starch (type C)， as raw materials， this study investigates the effect of soybean protein on the physicochemical properties of different crystal forms of starch. Scanning electron microscopy， Fourier transform infrared spectroscopy， rapid viscosity analyzer， differential calorimetry scanner， and simulated in vitro digestion were used to analyze the structure， function， and digestion characteristics of starch before and after treatment. The results showed that after the action of soybean protein on starch with different crystal forms， the absorption peak of O-H stretching vibration shifted towards a higher direction， and the values of T0 and Tp increased， as well as the gelatinization temperature. After interacting with soy protein， the RDS content of rice starch decreased to 37.56%， potato starch decreased to 7.48%， and pea starch decreased to 9.23%. The overall performance is enhanced particle aggregation， improved thermal stability， enhanced structural stability， and decreased digestibility. The structural differences between different crystal types of starch are as follows: Type A starch exhibits higher ordered crystalline regions and is less prone to aging； B-type starch exhibits the characteristics of easier gelatinization and greater reduction in digestibility； C-type starch exhibits a filamentous structure formed after compounding. The above results indicate that the protein has played a role in improving the properties of starch with different crystal forms， and there are differences in the performance between different crystal forms of starch.