Objective: The application of olive leaf, a by-product of olive oil production, in food industry was studied. Methods: Taking the yield of olive leaf polyphenols as the evaluation index, on the basis of single factor experiment, the effects of water bath temperature, extraction time and solid-liquid ratio on the yield of polyphenols were analyzed by Box-Behnken response surface method, the effects of olive leaf polyphenols on the oxidative stability of camellia seed oil were studied with peroxide value and acid value as indexes. Results: The optimum extraction conditions of polyphenols from olive leaves by water bath were as follows: ethanol volume fraction 50%, extraction time 1.0 h, solid-liquid ratio 1∶40 (g/mL), water bath temperature 72 ℃, and the yield of polyphenols from olive leaves was 5.86%. Olive leaf polyphenols had a good antioxidant effect on camellia seed oil, which was better than butyl hydroxyanisole (BHA), and had a synergistic effect with tert butyl hydroquinone (TBHQ) and BHA. Conclusion: The polyphenols extracted from olive leaves under the optimized conditions have a good antioxidant effect on camellia seed oil.