Objective： Optimize the preparation process of salt-soluble porcine liver protein and improve the utilization rate of porcine liver by-products. Methods： Taking the extraction rate as the index, the effects of NaCl concentration, pH, extraction time and solid-liquid ratio on the extraction rate of SSLP were analyzed, and the optimal preparation process was determined by orthogonal rotation optimization test. Taking water soluble liver proteins （WSLP） as the control, the functional characteristics （solubility, foaming, foam stability, emulsification, emulsification stability, etc.） of SSLP were compared and analyzed, and Fourier transform infrared spectroscopy （FT-IR） was used, the structural changes were analyzed by low field nuclear magnetic resonance （LF-NMR） and differential scanning calorimetry （DSC）. Results： The optimum extraction process of SSLP was NaCl concentration 0.4 mol/L, pH 8, extraction time 12.95 h, solid-liquid ratio 1∶4.6 (g/mL), and the extraction rate was 10.60%. FT-IR analysis showed that the absorption peak of characteristic functional groups of SSLP was obvious and in the secondary structure β-The relative content of corner was 39.91%, α-The relative content of helix was 13.55%, β-The relative content of folding was 21.32%, and the relative content of random curl was 25.23%; LF-NMR analysis showed that SSLP had higher bound water and higher water retention; DSC results showed that the denaturation temperature of SSLP was 78.68 ℃. Conclusion： SSLP prepared under optimal process conditions has better solubility, foaming, emulsification and emulsification stability than WSLP, which is a high-quality source for the development of pig liver protein products.