Abstract: This study aimed to investigate the effects of two cooking methods, atmospheric steaming and boiling, on the quality characteristics of vacuum freeze-dried Chinese yam powder, and to provide a basis for selecting appropriate processing techniques. Using Chinese yam from Dalong, Puning, Guangdong Province as the raw material, samples were subjected to atmospheric steaming and boiling treatments, followed by vacuum freeze-drying and milling. The physicochemical properties, nutritional components, and antioxidant activities of uncooked, steamed, and boiled yam powders were compared. The results showed that cooking treatments significantly altered the physicochemical properties of the yam powder. Boiling treatment (10 min) efficiently destroyed the starch crystal structure through the liquid water medium, increasing the solubility to 30.87 g/100 g and significantly improving the reconstitution property. In contrast, steaming treatment (20 min), due to limited moisture exchange, more effectively retained nutrients such as protein (9.86 g/100 g), allantoin (2741.81 μg/mL), and crude polysaccharides (1.39 g/100 g). Both cooking methods led to significant reductions in total flavonoid and total polyphenol contents, with a more pronounced decrease observed in the steamed group. Regarding antioxidant activity, the boiled group exhibited significantly higher DPPH radical scavenging activity and Fe²⁺ chelating capacity than the steamed group, although both groups showed lower values than the uncooked samples. Despite exhibiting the highest antioxidant activity, the uncooked sample had significantly lower solubility than the cooked samples. This study demonstrates that boiling treatment is beneficial for enhancing the reconstitution properties of the product, while steaming treatment is more conducive to nutrient retention, providing a theoretical basis and technical options for the targeted processing of Chinese yam powder.