Abstract: This study aimed to evaluate the effects of dragon fruit peel juice as a natural marinade on the physicochemical properties and flavor characteristics of beef steaks. Unmarinated steaks served as the control (CON), while a basic seasoning group (BSP) and a dragon fruit peel–marinated group (DFP) were prepared. The pH, color parameters, texture properties, and lipid oxidation levels of the samples were determined. Sensory evaluation, free amino acid profiling, and volatile flavor compound analysis—using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC–MS)—were conducted to systematically assess the influence of the marinade on steak quality and flavor. The results showed that marination with dragon fruit peel juice significantly increased the a^* value while reducing pH and fracture force (P<0.05), thereby effectively improving steak tenderness and color and inhibiting lipid oxidation. Free amino acid analysis indicated that glutamic acid and alanine were the major taste-active amino acids. A total of 536 volatile compounds were identified in the steaks, among which aldehydes and terpenes contributed prominently to the overall flavor. Compared with the CON group, the DFP group exhibited significantly lower levels of aldehydes and ketones but markedly higher levels of terpenes (P<0.05), promoting the development of intensified black-pepper-like and fruity notes and yielding a more balanced and enriched flavor profile. In conclusion, marination with dragon fruit peel juice significantly enhances the physicochemical and sensory qualities of beef steaks and optimizes their flavor characteristics, providing theoretical support for the development of natural antioxidant marinades and strategies for meat flavor modulation.