Due to the rapidly development in biomedical industry and the progressive needs in clinical trial, the clinical trial has remarkably increased during the past years. The composition of volunteers is not only included patients but also healthy subjects, which catered for the differences of research design of the trial. Thus, many ethical issues related to clinical trials have gained attention, particularly, the motivations of participating in clinical trials from healthy volunteers are crucial issue. The intention of the study is not only to understand the mainly motivation, perception and personality trait of healthy volunteers, but also to discuss the influence of demographic variables and personality trait on the motivation of volunteers participating clinical trials in Taiwan. This study was a cross-sectional survey research. The study sample included 196 healthy volunteers from three different biomedical clinical trial companies. The self-administered questionnaire contained 15 questions. The internal consistency reliability (£\) for the BFI scale was .789. One-way ANOVA and post-hoc analysis were used to examine the differences of the motivation in different demographic variables. In addition, hierarchical regression analysis was employed to investigate the determinants of different motivation. The results of the study showed most of the healthy volunteers were single male undergraduate students with age 20-24. The types of personality, openness¡Bextraversion and agreeableness, tended to be high tendentiousness. On the other hands, the subjects in neuroticism personality tended to be low tendentiousness. Moreover, the results showed the main motivation of the healthy volunteers is financial rewards, followed by free physical examination and the last is invitation by friends, respectively. According to the results of the study, the relatedness between the motivation of participating clinical trials and different variables showed that the elder subjects considered the free physical examination and promoting scientific and medical development as the mainly motivation, and showed less concern of companion invitation. Also, the subjects with higher education concerned the invitation by companion as less priority. Comparing with students, the waged volunteers showed less consideration of promoting scientific and medical development as motivation. Moreover, the healthy volunteer with average income between 10,000 to 19,999 NT considered mostly free physical examination, promotion of scientific and medical development and curiosity as the main motivation for the trial. The more involved in clinical trial the more consideration of other motivation and less concern of the invitation by companion. Furthermore, the subjects with more agreeableness personality trait tend to be more consideration of promoting scientific and medical development as their mainly motivation. In conclusion, the financial rewards is the priority consideration and shows remarkable influence to the motivation for the healthy volunteers, compared with the risk assessment and the consideration of personal health conditions. Thus, the clinical trials companies should balance between the rewards and health conditions. Particularly, the understandable and fully explanation as well informed consent before any trial implementation are necessary. Moreover, the researcher should be carefully concern about the health condition enrolling volunteers, in order to prevent the volunteer form harm.