Excessive fat is a common problem in sausage processing. Vegetable oils rich in n-3 fatty acid are a promising fat substitute due to their ability to reduce the risk of cardiovascular disease. Partially replacing animal fat with vegetable oils can improve the proportions of saturated fatty acids, unsaturated fatty acids and cholesterol in sausage and its nutritional quality, meeting people’s pursuit of health and nutrition. This review summarizes the effects of three types of oil-based fat substitutes (natural oil, pre-emulsified oil, and oleogel) on the processing, nutrition, sensory quality and safety of sausage. Recent progress in their application in reduced-fat sausage is summarized and future research directions are discussed, aiming to provide ideas for the development of new reduced-fat sausage products.