<p>Silent and oral reading are important reading modes. Chinese children begin to systematically learn these two reading modes in primary school. Previous studies have explored the developmental characteristics of eye movements during silent and oral reading among English-speaking children, but there has been no comparable research for Chinese children. In this study, eye-tracking data were collected from 240 primary school students (Grades 1–6) and 40 college students during silent and oral reading of sentences containing high-frequency and low-frequency words. We compared differences between adjacent grades and between each grade and adults to examine the developmental trajectory of eye movements in silent and oral reading, and explore the impact of reading mode on word frequency effect and individual difference in reading speed. Results indicated that as grades increased, fixation durations and regressions decreased, while saccade lengths increased during both silent and oral reading of sentences. Silent reading took a shorter fixation time than oral reading and showed greater development, with differences between the two modes becoming more pronounced after Grade 3. A stronger word frequency effect was observed in oral reading. Individual differences in reading speed influenced both silent and oral reading. The findings suggest that children's silent and oral reading have different developmental characteristics of eye movements. Furthermore, the unique linguistic features of Chinese may result in differences between Chinese and English children in reading modes.</p>