As the degree of population aging continues to deepen, the proportion of the elderly population is significantly increasing. This trend has placed higher demands on the design of age-friendly public facilities, including the need to meet the physiological, psychological, and social interaction requirements of the elderly. Focusing on the cognitive characteristics and processes of the elderly population, this study explores strategies and practices for designing age-friendly public facilities from the perspective of situational cognition. Through literature analysis and case study methods, the development issues of age-friendly public facilities are summarized, and the characteristics of age-friendly public facilities under the situational cognition perspective are discussed. Based on the three-level situational awareness model, a three-tiered progressive design strategy for age-friendly public facilities is proposed. The design strategies derived from the perception, comprehension, and prediction levels are as follows: stimulating multiple senses to promote in-depth perception, integrating cultural connotations to achieve multidimensional understanding, and providing diverse interactions to realize personalized experiences. Taking the public facilities in Yacheng Bay Science and Technology City in Sanya, China, as an example, design practices are carried out. The results show that incorporating situational cognition theory into the design of age-friendly public facilities can stimulate the in-depth perception of the elderly population, promote comprehensive understanding, and provide personalized experiences. This effectively enhances user satisfaction and positive emotional experiences among the elderly.