KIAA0319, a well-studied candidate gene, has been shown to be associated with reading ability and developmental dyslexia. In the present study, we investigated whetherKIAA0319affects reading ability by interacting with the parental education level and whether rapid automatized naming (RAN), phonological awareness and morphological awareness mediate the relationship betweenKIAA0319and reading ability. A total of 2284 Chinese children from primary school grades 3 and 6 participated in this study. Chinese character reading accuracy and word reading fluency were used as measures of reading abilities. The cumulative genetic risk score (CGS) of 13 SNPs inKIAA0319was calculated. Results revealed interaction effect between CGS ofKIAA0319and parental education level on reading fluency. The interaction effect suggested that individuals with a low CGS ofKIAA0319were better at reading fluency in a positive environment (higher parental educational level) than individuals with a high CGS. Moreover, the interaction effect coincided with the differential susceptibility model. The results of the multiple mediator model revealed that RAN mediates the impact of the genetic cumulative effect ofKIAA0319on reading abilities. These findings provide evidence thatKIAA0319is a risk vulnerability gene that interacts with environmental factor to impact reading abilities and demonstrate the reliability of RAN as an endophenotype between genes and reading associations.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12993-023-00212-z.