To avoid or retard the lipid peroxidation of meat products, antioxidants are commonly added. Considering the safety and health of additives in meat products, consumers prefer natural antioxidants rather than synthetic ones. Gentisic acid and epicatechin were identified as the major phenolic acid and flavonoid, respectively, of litchi flowers (LFs). The physicochemical properties of pork meatballs with or without dried LF powders (0.5%, 1.0%, and 1.5%, w/w) and tert-butylhydroquinone (TBHQ; 0.01%, w/w) were analyzed during a 4-week frozen storage period. LF and TBHQ decreased (p < 0.05) thiobarbituric acid reactive substance (TBARS) values but increased (p < 0.05) thiol group contents in meatballs. LF added to meatballs improved (p < 0.05) texture and water-holding capacity (centrifugation/purge losses) more than in the control group upon the storage. Although LF powders made meatballs redder and darker (p < 0.05) than the control and TBHQ groups, they did not affect the preference of panelists. The addition of 0.5% LF powders exhibited the best (p < 0.05) overall sensory panel acceptance. LFs may be an effective natural antioxidant to reduce lipid and protein oxidation for frozen cooked meat products.