This study employed the interview method to clarify the underlying dimensions of and relationships between students' scientific ontological and epistemic beliefs. Forty Taiwanese high school students were invited to participate in this study. Through content analysis of the participants' interview responses two ontological dimensions including "status of nature" and "structure of nature" were identified and found to be associated with each other. The two epistemic dimensions "knowledge" and "knowing" aligned with past literature were also categorised. Besides five pattern variations in terms of the aforementioned four dimensions were recognised based on the students' philosophical stances on their scientific ontological and epistemic beliefs. According to the Chi-square test results both dimensions of scientific ontological beliefs were significantly related to the two dimensions of scientific epistemic beliefs respectively. In general the students who endorsed a more sophisticated ontological stance regarding the status and structure of nature tended to express a more mature epistemic stance toward scientific knowledge and ways of knowing. The results suggest that the maturation of students' scientific epistemic beliefs may serve as a precursor and the fundamental step in promoting the sophistication of students' scientific ontological beliefs.