As the main component of cocoa, lipids are easily oxidized and deteriorated under high temperature and high humidity conditions, resulting in limited applications. Therefore, Pickering emulsion was prepared when octenyl succinic acid (OSA) starch was used as solid phase to stabilize cocoa oil phase, and cocoa essential oil (CEO) extracted by supercritical CO 2 was used as the oil phase. The preparation of Pickering emulsion was optimized and its stability was studied. The results showed that six main fatty acids were found in CEO. When the mass concentration of OSA starch was 250mg/mL and volume fraction of CEO was 5%, Pickering emulsion has the smallest particle size, 0.587μm. It was found that the emulsion was in a state of small droplets aggregation. The oil droplets were completely wrapped by starch and the interface was relatively smooth through optical microscopy, laser confocal microscopy and scanning electron microscopy. Stability experiments showed that the emulsion was relatively stable under the conditions of pH 5 and low particle concentration (0-0.3mol/L). After 21 days of storage, it was found that the particle size of Pickering emulsion increased from 0.587μm to 1.160μm when oil phase volume fraction was set at 5% with the increase of storage time. The particle size of Pickering emulsion was increased approximately by 1.500μm and the maximum particle size reached 2.760μm when the starch mass concentration was set between 50mg/mL and 300mg/mL. The experimental results showed that the OSA starch-CEO Pickering emulsion had good stability.