Abstract: In order to improve the functional properties of porcine heart protein and improve its application feasibility in the food industry, this study modified porcine heart protein (PHP) by ultrasonic (frequency of 20 kHz, power of 350 W, treatment for 8 min, working 5 s with 2 s intervals) combined with different concentrations of ethanol (0~80%). The changes of molecular structure, microstructure, active sulfhydryl content, surface hydrophobicity, solubility, emulsification, emulsion particle size and emulsion Zeta potential of modified PHP were determined. The results showed that the primary structure, secondary structure and microstructure of PHP were significantly changed under the combined action of ultrasonic and 40% ethanol modification. The ultraviolet absorption intensity of PHP was the largest, the active sulfhydryl content and surface hydrophobicity were the largest. The solubility of protein was significantly reduced (P<0.05), the emulsifying activity and emulsifying stability were the best, the particle size of protein emulsion was the smallest, and the absolute value of Zeta potential was the largest. Considering the improvement effect of PHP emulsification characteristics, ultrasonic combined with 40% ethanol modification treatment is the best modification condition for PHP.