Pulmonary infections pose significantly greater threats to the elderly than to younger populations. At the same time, Pseudomonas aeruginosa, a major opportunistic pathogen, frequently causes a typical bacterial chronic infection in clinically vulnerable elderly individuals. To understand the underlying mechanisms of chronic infection in the elderly, a reliable and stable model using aged mice is essential. However, initial attempts using intratracheal instillation of planktonic P. aeruginosa caused 100% mortality, prompting us to optimize current infection methodology in regular young mice. By embedding bacteria in agar beads for intratracheal delivery, we successfully established persistent P. aeruginosa colonization with significantly improved survival. This model provides a crucial platform for elucidating the molecular mechanisms of host-pathogen interactions during chronic infection in the context of aging. Additionally, it offers vital insights into age-specific immune responses against pulmonary bacterial infections and facilitates the development of novel therapeutic strategies tailored for the elderly population.