This paper aims to study the adaptive aging design strategy of smart TV voice interaction interface based on language cognitive aging mechanism. The phenomenon and underlying mechanism of language cognitive aging in the process of language generation and language understanding are studied, and the main factors that may affect the interaction efficiency and interaction experience of the elderly in the process of human-computer voice interaction are summarized. The KANO model is used to classify the design factors affecting the satisfaction of elderly users in the process of using a smart TV, and the importance of user needs is recognized. Based on this, an aging-friendly design strategy is proposed for the voice interaction interface of smart TV. From the perspective of user language cognition, moderate compensatory design strategies such as a simple and natural language interaction environment, flexible and inclusive information recognition strategy and accurate and effective voice output iteration can effectively reduce the obstacles to voice interaction between elderly users and smart TV, improve the interaction performance and optimize the user experience.