The study aims to use thermal processing to enhance sodium release from surimi matrix during oral processing and therefore improve the saltiness perception. Surimi gels were prepared by one- and two-stage heating, containing water bath heating (WB90), microwave heating (MW10), two-stage water bath heating (WB40+WB90), and water bath combined with microwave heating (WB40+MW10). The physicochemical properties including gel strength, protein degradation, and microstructure of surimi gels were compared. The water and sodium mobility of surimi gels were characterized by ¹H low field NMR and ²³Na NMR. Sodium release from matrix during oral processing and sensory evaluation of saltiness difference were employed to verify the enhancement effect of saltiness perception caused by thermal processing. WB40+MW10 improved surimi gel strength by reducing the degradation of myosin heavy chain. Microstructure observations showed that WB40+WB90 gels had a relatively rough and loose microstructure with curved small gaps, whereas WB40+MW10 gels exhibited a denser microstructure. The water and sodium mobility of WB40+MW10 gels (T₂₁ 88.08 ms, D 6.68 × 10⁻¹⁰ m²/s) were significantly higher than those of WB40+WB90 gels (T₂₁ 83.10 ms, D 6.35 × 10⁻¹⁰ m²/s). WB40+MW10 gels eliminated the tortuosity effect of water and sodium diffusion, resulting in 1.12 times higher sodium release than WB40+WB90 gels. The triangle sensory evaluation also showed that WB40+MW10 gels were perceived as saltier than WB40+WB90 gels, achieving a 15% salt reduction effect. This study provides a promising heating method to improve the saltiness perception of fish products by enhancing sodium release during oral processing.