To counteract the negative effects of conventional freezing methods on frozen surimi products, the present study investigated the effects of magnetic field (MF) freezing in combination with different amounts of curdlan (CUR) on oxidative denaturation, structural alterations, and thermal stability of myofibrillar protein (MP) in shrimp surimi. The results indicated that the intervention of magnetic fields alone improved the quality of frozen muscle proteins. Under the dual intervention of magnetic field-assisted freezing and CUR, small ice crystals formed with MF6 treatment resulted in significantly lower solubility, turbidity, and mean particle size than the control group (p < 0.05). Moreover, the oxidation of MP was also significantly slowed down by inhibiting the formation of hydrophobic groups and carbonyl groups, maintaining a high content of sulfhydryl groups. MF6 also exhibited a high Ca2+-ATPase activity. The α-helix content, the increase in fluorescence intensity under this condition also tend to make the secondary and tertiary structures of myofibrillar protein more stable. Meanwhile, electrophoretic profiles and CLSM showed that this condition maintains the integrity of the MP. In addition, the MF6 samples also had high protein thermal stability. However, excess CUR reduces the excellence of MP cryoprotection. As a result, MF6 has better protection and improvement effects on protein function, structure and thermal stability, and CUR was also found to have the potential for cryoprotectant development.