In the present study, we explored the perceptual span of typically developing Chinese children in Grade 3 (G3) during their reading of age-appropriate sentences, utilizing the gaze contingent moving window paradigm. Overall, these Chinese children had a smaller perceptual span than adults, covering only one character leftward and two characters rightward of the currently fixated one. In addition, individual differences in reading ability (i.e., number of characters correctly read aloud per minute) influenced the size of the perceptual span. Fluent readers' reading and eye-movement parameters benefited from previewing the third upcoming characters, whereas non-fluent readers reached their asymptotic performances in a smaller window revealing rightwards by only two characters. These results suggest that the perceptual span is modulated dynamically by reading ability. Non-fluent readers need to focus their attention on foveal words, leading to narrowed perceptual span and reduced parafoveal processing.