In order to safely and effectively prolong the shelf life of food, zein and sodium caseinate were utilized to prepare composite nanoparticles loaded with carvacrol by pH-driven method. The zein/sodium caseinate composite nanoparticles have a good encapsulation efficiency (77.96% ~ 82.19%) for carvacrol. Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) analysis show that carvacrol was loaded successfully. Scanning electron microscopy (SEM) results show that the composite nanoparticles are spherical with a particle size range of 50 ~ 200 nm, and have the strong antioxidation activity and antibacterial activity. When the composite nanoparticles were used in food packaging, they could effectively inhibit food spoilage and prolong the shelf life of food, showing potential application prospects in food industry.