Abstract: Docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid, is mainly derived from fish oil and algal oil. Algal oil has a high DHA content and good safety, and is widely used in the food industry. DHA algal oil has been proven to have functions such as promoting brain development, regulating immunity, reducing inflammatory responses, preventing cardiovascular diseases, antioxidation, and anti-cancer effects. This article introduces the lipid composition of DHA algal oil, as well as the digestion and absorption of DHA in algal oil. It also reviews the health benefits, mechanism of action of DHA algal oil, and its current application status in health foods in China. The aim is to provide some references and basis for the research, development and application of DHA algal oil in health foods in China.