Tourist risk perception is a theoretical topic of great interest, but few studies have specifically investigated vulnerable groups of people with chronic illnesses, chronic illnesses may be part of their daily lives, affecting individuals' health risk awareness and complicating travel decisions. This study is one of the first in the tourism field to explore risk perception and travel decision-making among chronically ill tourists. Adopting protection motivation theory as a guiding framework, 504 chronically ill tourists with different stages and types of illness were investigated to assess patients' perceived health risks and actual travel intentions in a quantitative method. It was found that the travel behavior and self-protective behavior of chronically ill tourists depended on the strength of risk perception, which was mainly influenced by perceived threat, response cost and self-efficacy. Further studies confirmed the role of risk perception as a mediator between PMT factors and decision-making behavior and the moderating effect of Plog psychological type. The study reveals the logic that shapes the decision-making behaviors of chronically ill tourists' travel and expands accessible tourism from creating enjoyable experiences to facilitating positive travel, and the findings can provide theoretical guidance for the design of destination experiences and encourage the exploration of travel behaviors of people with chronic illnesses.