With the development of information technology and the aging of the world’s population, how to design websites that are easy to access and use for the elderly is becoming an increasingly important issue. However, due to the cognitive aging of the elderly in terms of vision, memory, and processing speed, they often face varying degrees of cognitive difficulties when browsing the web. The cognitive difficulty cause a significant negative impact on the user experience of the elderly browsing the web and hinders the integration of the elderly into the information era. In order to reduce the cognitive difficulties of the elderly when browsing the web, and to explore quantifiable principles of age-appropriate web design, This study manipulated four quantitative indicators: color, contrast, page layout and operation logic to design the web page, and then the elderly over 60 years old were invited to rate different web page designs through a questionnaire survey. Finally, a comprehensive mathematical model for aging web design was built based on the data from the questionnaire survey. The research results provide a quantitative idea and a mathematical model that integrates multiple indicators for aging-appropriate web design.