Krill oil (KO) exhibits several biological actions, particularly providing distinct advantages for cognitive health in the aged. Nonetheless, its inadequate water solubility, pronounced flavor, and vulnerability to oxidative degradation restrict its utilization in the food sector. Encapsulation provides a solution, and the study of natural, suitable wall materials is crucial. This study employs endogenous krill protein (KP) and krill chitosan (CS) as encapsulating agents. It utilizes a complex coacervation technique to encapsulate KO, thereby broadening its application and successfully incorporating it into senior milk powder. The microcapsules have the best properties when the KP + CS complex to krill oil ratio is 1:1. They are able to encapsulate 77.96 % of the oil, stay stable at high temperatures (with little mass loss), and stay stable over time (with a peroxide value increase of only 4.51 mmol/kg). Moreover, the release rate in simulated intestinal conditions reaches 83.26 %. When added at 0.8 % to senior milk powder, it imparts the highest nutritional value without significantly affecting the flavor. Thus, this study provides valuable insights for enhancing the stability of krill oil and its application in the food industry.