Abstract: 【Objective】 To study the preparation of conjugated linoleic acid from pepper seed oil by isomerization alkali in order to obtain high conversion of pepper seed oil conjugated linoleic acid. 【Method】 The Conversion Rate of Conjugated Linoleic Acid was used as an indicator of investigation, the main influencing factors were reaction time, reaction temperature, alkali oil ratio and dissolved oil ratio, and the effects of different factors on conjugated linoleic acid conversion of pepper seed oil was analyzed by CCD. After that, the preparation process of conjugated linoleic acid from capsicum seed oil was determined, and the oxidation stability of conjugated linoleic acid between pepper seed oil and pepper seed oil was compared by Schaal oven accelerated test. 【Result】 The optimal technical conditions are determined as follows by establishing the quadratic response regression model: The reaction temperature was 169℃, the reaction time was 4.4 h, Alkali oil ratio M(KOH):M (Pepper seed oil) was 0.2, Dissolved oil ratio M(polyethylene glycol):M(Pepper seed oil) was 1.7, and the conjugation conversion could reach 84.60%. Its oxidation stability was better than that of pepper seed oil. 【Conclusion】 The process conditions of conjugated linoleic acid in pepper seed oil are optimized by response surface methodology, and the conjugated linoleic acid in pepper seed oil with good stability is obtained.