Red wine polyphenols carbon dots (P-CDs) with antioxidant properties were synthesized and extensively characterized to determine their size, morphology, and microstructure. Their potential to enhance oxidative stability in sunflower oil was thoroughly evaluated and compared with traditional antioxidants like butyl hydroxyanisole (BHA) and n-propyl gallate (PG). The P-CDs were found to be spherical nanoparticles, generally smaller than 10 nm, confirming their nanoscale characteristics. Further analysis revealed that the unique properties of the P-CDs were largely due to oxygen-containing functional groups and a highly defective graphite structure, providing them with distinct physical and chemical attributes. In scavenging tests with DPPH and ABTS radicals, P-CDs demonstrated outstanding performance, suggesting their promising application in the antioxidant field. Additionally, the P-CDs effectively inhibited the oxidative rancidity process in sunflower oil, offering a novel approach to improving oil's oxidative stability. A significant finding was that when 0.01% of red wine polyphenol carbon dots were added, they outperformed both BHA and PG in inhibiting the accumulation of anisidine, reducing total polar compound content, and preserving the oil's fatty acid composition, color, and viscosity. This discovery not only broadens the application scope for P-CDs in antioxidant research related to oils, but also supports their practical implementation in the food industry.