Purpose: To screen and identify immunologically active components in the hydrolysate of tuna protein. Method: Tuna protein was hydrolyzed using trypsin， and separation， purification， and identification were performed using a combination of Sephadex G-25 gel chromatography and liquid chromatography-mass spectrometry (LC-MS/MS). The evaluation criteria included the relative proliferation rate， phagocytic ability， nitric oxide(NO) production capacity， and cell cycle distribution of RAW264.7 cells. Components with strong immunological activity were selected， and their structures were identified. Results: After purification by Sephadex G-25 and Sephadex G-15 chromatography， the isolated FF1 fraction exhibited strong immunological activity， with a relative proliferation rate of 73.66%， phagocytic ability of 70.04%， and NO production capacity of 4.82 μmol/L in RAW264.7 cells. Conclusion: The FF1 fraction obtained after Sephadex G-15 separation demonstrated strong immunological activity， and two potential immunologically active peptide sequences were screened from this fraction， namely， Gly-Asp-Ala-Glu-Met-Glu-Ala-Tyr-Gly-Lys (GDAEMEAYGK) and Leu-Leu-Tyr-Gly-Gly-Ser-Val-Thr-Gln-Thr-Cys-Lys (LLYGGSVTQTCK). This study provides important theoretical references for the development and utilization of immunologically active peptides from tuna.