Lutein is a natural pigment with various beneficial biological activities, but its poor water solubility, chemical instability, and low bioavailability limit its application in food processing. In this study, modified casein (CAS-OCS NPs)-based Pickering emulsions were constructed under the combined effect of TGase-type glycation and ultrasound treatment as delivery systems for lutein fortification. Pickering emulsions based on CAS-OCS NPs enhanced the encapsulation efficiency of lutein (87.04 ± 0.30 %). The modification treatments improved the emulsifying properties, environmental stability, and digestive stability, as well as the delivery capability of lutein and antioxidant activity in simulated in vitro gastrointestinal digestion. After glycation modification, the lutein release rate of CAS-OCS NPs-based Pickering emulsions after in vitro digestion was higher than that of untreated casein-based Pickering emulsions, and the maximum release rate was 55.44 ± 0.50 %. Moreover, the CAS-OCS NPs-based Pickering emulsions showed improved lutein bioaccessibility, reaching the maximum value of 58.52 ± 0.52 %. These findings demonstrated the suitability of TGase-type glycation and ultrasound treatment for the preparation of Pickering emulsions to deliver bioactive compounds.