People all over the world face the moment of decision making every day in many aspects of life including health and medical decision making. People usually make decisions in the direction of avoiding risk, but sometimes take risks intentionally or without being aware of it. This study examined risk perception on vaccines and diseases that could be prevented by vaccines and explored how people make decisions on vaccination, especially for flu vaccine and premium vaccines (e.g., pneumonia vaccine and meningitis vaccine). I have reviewed the previous theory (e.g., fuzzy-trace theory) and research on risk perception and decision making. Fuzzy-trace theory (FTT) is a dual-process theory of memory, reasoning, judgment, and decision-making, and FTT contrasts two types of judgement: gist and verbatim mental representations. Gist representation reflects a subject, intuitive, and impressionistic understanding of an event, whereas verbatim representation reflects precise words, numbers, and objective facts. To examine the theory in the vaccination decision-making area, a total of 141 participants in many age groups were recruited in this research and completed a survey by providing answers to the online questionnaires, and the results were statistically analyzed. Results indicated that risk perception of being vaccinated was negatively correlated to the previous vaccination decision and future intention, whereas risk perception on not being vaccinated was positively correlated to the past and future vaccination decision. The risk of being infected had a positive correlation with the past and future vaccination only pneumonia showed significant relationships. Also, it was found that gist was found to have relatively higher dominance than verbatim does in vaccination decisions of flu and pneumonia in total sample and students sample.