To investigate safe and effective methods for Salmonella typhimurium control, the synergistic bactericidal mechanism of ultrasound (US) combined with carvacrol nanoemulsion (CN) against S. typhimurium was evaluated, along with its application in cabbage. CN was prepared using ultrasonic emulsification. The bactericidal effects, changes in bacterial cell morphology, intracellular content leakage, reactive oxygen species (ROS) levels, N-phenyl-1-naphthylamine (NPN) uptake, and malondialdehyde (MDA) content of S. typhimurium were evaluated following the treatment. Additionally, the efficacy of this treatment in eliminating S. typhimurium on cabbage surfaces and its impact on cabbage color and firmness were investigated. The results demonstrated marked synergistic bactericidal effects of the US+CN treatment against S. typhimurium compared with individual treatments, with bactericidal synergy values of 1.35 and 1.33, respectively. Bacterial cell membrane damage and increased permeability were also observed, along with cell shrinkage and collapse. ROS levels and MDA content increased significantly to 1 866.99 and 1.25 nmol•mL-1, respectively, indicating intensified oxidative stress. Furthermore, the US+CN treatment reduced S. typhimurium viability on cabbage surfaces by 0.89~2.01 lg CFU/g, with no marked alterations in cabbage color or firmness. These findings demonstrate that the US+CN treatment synergistically inactivates S. typhimurium and enhances the safety of fresh agricultural products, thereby offering a safe, efficient, and highly promising sterilization method for the food industry.