Abstract: As a novel alternative edible protein, microalgal protein has garnered significant attention due to its high protein content, comprehensive and balanced essential amino acid profile, and abundant bioactive components. Compared to animal and plant proteins, microalgal cultivation does not rely on arable land, utilizes CO₂ and wastewater resources, and achieves protein yield per unit area far exceeding traditional crops, demonstrating remarkable comparative advantages and sustainable development potential. This paper reviews the nutritional value, functional properties, separation and purification methods, and application scenarios of microalgal protein. On this basis, it points out that microalgae protein faces challenges such as high production costs, low digestibility and absorption rates, and poor stability in large-scale cultivation. In the future, it is necessary to fully promote the large-scale application of microalgae protein in sustainable food supply systems through genetic improvement of algal strains, optimization of cultivation processes, and safety evaluation of applications.