Oysters are commonly used as ingredients in pre-made dishes, but their quality deteriorate with increased storage time. To mitigate quality degradation in prepared oysters, the effects of freezing at -18 ℃, -35 ℃, and -80 ℃; liquid nitrogen flash freezing at −80 ℃; and immersion freezing were investigated. Freezing rate, physicochemical indicators, microstructure, and volatile components of different samples were compared to evaluate the effect of different freezing methods. The results showed significant differences in the time required to pass through the maximum ice crystal formation zone (P<0.05) across different freezing methods (89, 57, 32, 5, and 14 min, respectively). After 30 days of frozen storage, the total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA) levels of all oyster samples were below the spoilage thresholds for aquatic products. Hardness decreased by 51.89%, 48.65%, 44.86%, 38.92% and 43.24%, respectively. Moreover, liquid nitrogen flash freezing and immersion freezing did not change the texture of the samples considerably. Microstructure analysis showed that immersion freezing had similar effects to liquid nitrogen flash freezing, resulting in a tighter structure and better reduction. Volatile flavor substance analysis revealed that immersion freezing had a positive effect on prepared oysters by delaying fat and protein oxidation, thus reducing sulfur compound concentration. Thus, both liquid nitrogen flash freeze and immersion freezing are advantageous in maintaining oyster quality, but immersion freezing is more cost-effective. The results of the study serve as a reference for the aquatic product processing and pre-made dish production industries.