As the major component of walnuts, walnut protein is a high-quality plant protein resource, but it has low solubility and poor emulsifying properties, which restricts its application in the food industry. In recent years, structural modification and functional optimization of walnut protein through physical, chemical, biological and combined modification technologies have become a research hotspot. This paper reviews the composition and properties of walnut protein as well as the latest progress in its modification technologies, and discusses the application of modified walnut protein in the food industry, in order to provide a theoretical reference for the high-value utilization of walnut protein.