Under the background of the accelerating of aging population and the rapid development of intelligent product market for the elderly, this paper explores the emotional preference of elderly users for the appearance of service robots.Eye movement evaluation is the main method to study the vision and emotional cognition of the elderly. The 65 years old (the basic age) elderly users were selected as the research objects. The positive pictures of four kinds of service robots for the elderly in the market, including human, animal-like, anthropomorphic and object-shaped, were selected as stimulus materials. 15 healthy elderly people participated in the experiment with eye tracking as the main method and the subjective questionnaire and ECG as the auxiliary methods to explore their physiological and psychological characteristics when being confronted with the different service robots with different appearance design elements. Based on the three kinds of measurement data, they show that the elderly users pay more attention to the head shape of the service robot, the black color is more suitable for the elderly people's visual and sensory preferences, and the appearance shape of the human service robot is more popular. The results of this study can provide a theoretical and practical basis for the appearance design of future elderly service robots.