In this study, five polysaccharides (κ-carrageenan, ι-carrageenan, gellan gum, chitosan and konjac glucomannan) were used as an additive to improve the quality of mackerel surimi gel, mainly in terms of textural properties, water holding capacity (WHC), water distribution, dynamic rheology, differential scanning calorimetry (DSC), chemical interactions, microstructure and SDS-PAGE. The results showed that the presence of ι-carrageenan obviously increased WHC (73.56%–82.63%) and shortened the relaxation time T₂₂ (63.03–54.89 ms) , signifying the strong combination within surimi proteins and ι-carrageenan. In addition, the addition of κ-carrageenan, ι-carrageenan and gellan gum resulted in a significant improvement in the gel strength, hardness, chewiness and energy storage modulus (G'). To be specific, the gel strength increased significantly from 6943.07 g·mm to 12456.99, 12603.14 and 8727.81 g·mm, but there was no apparent improvement in whiteness. DSC results indicated that different types of polysaccharides elevated the denaturation temperature and enthalpy of surimi gels, suggesting a high degree of cross-linking. Furthermore, the chemical forcing results indicated that disulfide bonds and hydrophobic interactions were dominant in the surimi gel system and the addition of carrageenan clearly enhanced the hydrogen bonds compared with the control group. Moreover, the microstructures of surimi gels combined with carrageenan showed homogeneous honeycomb network with dense and smooth pores and participation of polysaccharides could not change the aggregation and degradation of proteins. The present study might be necessary for promoting the high-value use of aquatic surimi products with the combination of polysaccharides and the application of polysaccharides in food industry.