Abstract: In this study, the effects of inulin, as a fat substitute, on the quality of mung bean protein low-fat plant yogurt were investigated. The mung bean protein yogurt with 3% of sunflower oil was taken as a high-fat yogurt control, the fat-replacement effect of inulin was evaluated by analyzing the effects of different concentrations of inulin (2%, 4% and 6%) on the viscoelasticity, texture, water holding capacity, microstructure and sensory quality of mung bean protein low-fat yogurt (with 1% of sunflower oil). The results indicated that compared with the mung bean protein high-fat yogurt, the viscoelasticity, hardness, chewiness, water holding capacity, and sensory quality of mung bean protein low-fat plant yogurt with 2% of inulin were equal to those of mung bean protein high-fat yogurt (P>0.05), with a uniform and dense protein network structure. The hardness and chewiness of mung bean protein low-fat yogurt with 4% inulin were significantly improved by 21.56% and 32.34% (P<0.05), respectively, and the water holding capacity reached 88.55%. At the same time, mung bean protein low-fat yogurt also showed a dense network structure, and the overall sensory quality was the best. The viscoelasticity, hardness, chewiness, and water holding capacity of mung bean protein low-fat yogurt with 6% of inulin were significantly higher than those of mung bean protein high-fat yogurt (P<0.05). However, the microstructure of mung bean protein low-fat yogurt with 6% of inulin showed porous and uneven protein network structure, the texture and mouthfeel were deteriorated, and the overall sensory quality was the worst. Therefore, these results proved that 2%~4% of inulin could significantly improve the quality of mung bean protein low-fat yogurt, and had a better fat-replacement effect. The results in this study could provide a theoretical basis for the development of high-quality mung bean protein low-fat yogurt.