Abstract: Freezing and thawing are often required for the preservation and market value of seedless lychee. However, the traditional freezing and thawing have severely limited the quality of fruits and vegetables, due to the time-consuming, inefficient, and damage rate. Fortunately, dry ice jet quick freezing and microwave thawing have emerged to gain much attention in recent years. Therefore, this study aims to explore the effects of different quick-freezing and thawing on the quality of the seedless lychees. Two freezing modes (dry ice jet quick freezing and conventional quick freezing) were combined with four thawing modes (room temperature, water bath, microwave, and refrigerated thawing). A series of experiments were designed for the dry ice jet quick freezing of seedless lychee. A comparison was made on some indicators, such as the freezing time, thawing time, vitamin C content, drip loss rate, pH value, titratable acidity (TA), texture properties (hardness, elasticity, and chewiness), total phenolic content, and total soluble solids (TSS) content. A systematic evaluation was also made on the effects of different freezing-thawing on the quality of seedless lychee. The experimental results demonstrated that the dry ice jet quick freezing with microwave thawing (DM) performed best across all indicators. The freezing time of DM was only 181 s, significantly shorter than the 2.2 h required for conventional freezing. The thawing time of DM was only 2.86 min, far faster than the rest, and greatly saving time costs. In terms of quality preservation, the DM exhibited the lowest drip loss rate (4.87%) and the least vitamin C loss (0.42×10^-2 mg/g), significantly outperforming the rest treatments. Additionally, the DM effectively maintained the pH value and titratable acidity (TA) of lychee fruits. The pH value of DM-treated lychee was 3.83, close to that of fresh lychee (3.81), with only a 0.52% increase. The TA of DM-treated lychee was 0.66%, similar to the 0.64% of fresh lychee, with only a 3.13% increase. In terms of the texture properties, the DM-treated lychee showed elasticity (2.38 mm), hardness (8.37 N), and chewiness (10.13 MJ) close to those of fresh lychee, with reductions of only 2.9%, 1.5%, and 1.1%, respectively. A significant advantage was maintained in the fruit texture. Furthermore, the TSS content of DM-treated lychee was 17.86 °Bx, closest to the 18.00 °Bx of fresh lychee, while the total phenolic content was 0.94 mg/g, significantly higher than the rest treatments, indicating its excellent performance in retaining the nutritional components. Sensory evaluation results showed that the DM-treated seedless lychee was ranked the highest in appearance, texture, aroma, taste, and flavor, with scores of 8.7, 8.5, 8.8, 8.6, and 8.7, respectively, close to the 9.0, 8.8, 9.0, 8.9, and 9.0 of fresh lychee and significantly higher than the rest (P< 0.05). The microstructural analysis further validated that the DM treatment shared minimal damage to cell walls and membranes, as well as uniform and fine ice crystal distribution, effectively maintaining the fruit cell integrity and water retention capacity. In conclusion, the dry ice jet quick freezing with microwave thawing can be expected to maximize the preservation of seedless lychee quality. This finding can also provide important theoretical insights for the more efficient freezing preservation, storage, and transportation of seedless lychee.