One of the ways to prevent the oxidation of oils and fats is the addition of antioxidants, but since synthetic antioxidants may have adverse effects on the body, they are gradually removed from the list of antioxidants. Therefore, it is necessary to produce and produce natural varieties. Therefore, the aim of this study was to investigate the possibility of using natural extract extracted from Carduus pycnocephalus L. to prevent oxidation of soybean oil and compare it with essential oil. In this study, the extraction process was performed by ultrasound technology with 3 factors of 3 levels including concentration (200, 500 & 800 ppm) time (10-30 minutes) and temperature (55-35°C) by response surface methodology. To investigate the antioxidant effect of different concentrations of extracts on oxidative stability of soybean oil, peroxide value and thiobarbituric acid reactive index were used. The optimization results showed that the optimum conditions were: temperature 48.483 ° C and time 299. 201 min and concentration of 594.745 ppm. According to the optimization results of free radical scavenging and Folin compounds were reported 32.537% and 40.378%, respectively. The results of oxidative stability of oil showed that both extracts and essential oils were effective in preventing oil oxidation. Also, the type of extracted material was related in two ways. Since the extract has the most antioxidant effects in the oil and is more effective than the essential oil in the oil, it can be a good alternative to synthetic antioxidants in frying oils.