Abstract: To improve the gel quality of surimi products, this study investigated the effects of adding Citrus fiber at different mass fractions (0%, 0.5%, 1.0%, 1.5%, 2%) on the gel properties and microstructure of threadfin bream surimi. The results demonstrated that as the amount of citrus fiber increased, the gel strength, hardness, water holding capacity (WHC), and immobilized water content of surimi gel exhibited an initial increase followed by a subsequent decrease, and the maximum values of 5702.55 g·mm, 3577.74 g, 89.45% and 92.58% were reached respectively when the Citrus fiber concentration was 1.5%. Both the storage modulus and loss modulus also attained their peak values at this level, accompanied by the formation of a denser, smoother, and finer-pored gel network structure. Furthermore, compared with the control group, the incorporation of Citrus fiber significantly enhanced the whiteness of the surimi gel (P<0.05), reduced cooking loss, promoted the unfolding of the protein secondary structure, and facilitated the transformation of α-helices into β-sheets. However, when the citrus fiber addition level was 2.0%, the network structure of surimi gel became loose, with large holes appearing, and the hardness, gel strength and WHC of the gel decreased accordingly. In conclusion, the addition of 1.5% Citrus fiber effectively improved the gel properties of Nemipterus virgatus surimi, providing a reference for the application of citrus fiber in surimi products.