The extraction technology of red fresh pepper S06 was optimized by ultrasonic assisted method. First, the best ethanol petroleum ether mixture ratio, solid-liquid ratio, extraction temperature and time were obtained by single factor experiment. Then the extraction procedure of capsaicin was optimized by L9(34) orthogonal experiment. The results showed that the optimal extraction condition was ethanol petroleum ether mixture ratio of 3∶7, the ratio of material to liquid is 1∶5.5, the temperature is 60 ℃, and the time is 2.0 h; The optimal condition for the purity was that the mixture ratio of alcohol and petroleum ether was 3∶7, the ratio of material to liquid is 1∶5.5, the temperature is 65 ℃, and the time is 1.5 h. Compared with the traditional ethanol extraction method, the optimized extraction rate and purity increased by 27.8% and 53.8% respectively, and the yield of capsaicin was(4.961±0.232)‰, the purity of capsaicin was (8.568±0.245)%. The method increased the extraction rate of capsaicin, lowed the extraction cost per unit capsaicin, and improved the whole procedure.