This study investigates the characterization, stability, and antioxidant activity of vanilla nano-emulsions and their complex essential oils. Vanilla essential oil (EO), known for its unique aroma and flavor, is volatile and unstable, limiting its application. To enhance its stability, vanilla EO was compounded with cinnamon EO to create composite nano-emulsions (C/VM and C/VT). Transmission electron microscopy (TEM) showed that the nano-emulsions were spherical with some flocs observed in C/VM and C/VT. The average droplet sizes of C/VM and C/VT increased by only 14.99% and 15.01% after heating at 100°C for 20 min, and remained below 120 nm after 24 days of storage at 25°C. The instability indices of C/VM and C/VT were reduced by 34.9% and 39.08%, respectively, compared to their counterparts. Antioxidant experiments showed that the presence of composite essential oil flocs had no significant effect on antioxidant capacity. The results indicate that the improved stability of the composite essential oil nano-emulsions is beneficial for broadening the application of vanilla essential oil emulsions. The study also explored the effects of thermal, pH, and centrifugal stability on the nano-emulsions, and found that the composite essential oil nano-emulsions (C/VM and C/VT) showed better stability than the individual essential oil emulsions (C, VM, VT). The antioxidant activity of the nano-emulsions was also assessed, and the results showed that the vanilla essential oil had a better scavenging ability of ABTS radicals compared to the cinnamon essential oil. The study concludes that the composite essential oil nano-emulsions can improve the stability and application range of vanilla essential oil emulsions.This study investigates the characterization, stability, and antioxidant activity of vanilla nano-emulsions and their complex essential oils. Vanilla essential oil (EO), known for its unique aroma and flavor, is volatile and unstable, limiting its application. To enhance its stability, vanilla EO was compounded with cinnamon EO to create composite nano-emulsions (C/VM and C/VT). Transmission electron microscopy (TEM) showed that the nano-emulsions were spherical with some flocs observed in C/VM and C/VT. The average droplet sizes of C/VM and C/VT increased by only 14.99% and 15.01% after heating at 100°C for 20 min, and remained below 120 nm after 24 days of storage at 25°C. The instability indices of C/VM and C/VT were reduced by 34.9% and 39.08%, respectively, compared to their counterparts. Antioxidant experiments showed that the presence of composite essential oil flocs had no significant effect on antioxidant capacity. The results indicate that the improved stability of the composite essential oil nano-emulsions is beneficial for broadening the application of vanilla essential oil emulsions. The study also explored the effects of thermal, pH, and centrifugal stability on the nano-emulsions, and found that the composite essential oil nano-emulsions (C/VM and C/VT) showed better stability than the individual essential oil emulsions (C, VM, VT). The antioxidant activity of the nano-emulsions was also assessed, and the results showed that the vanilla essential oil had a better scavenging ability of ABTS radicals compared to the cinnamon essential oil. The study concludes that the composite essential oil nano-emulsions can improve the stability and application range of vanilla essential oil emulsions.