This study used a Chinese-language version of the Index of Science Reading Awareness (ISRA) to investigate metacognitive awareness and the Reading Comprehension of Science Test (RCST) to explore comprehension of science text by Taiwanese students. Structural equation modeling (SEM) results confirmed the validity of the underlying models of metacognitive awareness and comprehension of science text. First, the Interactive-Constructivist Model of Reading (ICMR) comprises three clusters of knowledge, in which the comprehension of science text was affected by metacognitive awareness and prior knowledge about language and science; second, the effect of prior knowledge on the RCST was mediated by metacognitive awareness of science reading. The implications of these findings for science curriculum aiming to activate students' prior knowledge and raise students' metacognitive awareness on science reading are discussed; as well, directions for future research are provided.