There is currently a lack of a more integrated perspective on reading literacy education. In preschool reading activities, it's important to maximize an individual's potential for reading literacy development with limited nurturing energy. Based on self-regulated theory and metacognitive models, this study explored the pathway model of the influence of joy (interest in reading) and instruction (metacognitive strategy) on reading literacy in this context, with further investigation in different family contexts. Using PISA 2018 data, the model results showed that 1) preschool home reading activities contribute to individual student's interest in reading; 2) interest in reading, as a mediating variable, positively predicts reading literacy in preschool home reading activities; 3) reading instruction without interest in reading (purely metacognitive strategies) fails to produce a significant mediating effect; 4) there is a significant chain mediation from preschool family reading activities to interest in reading, to metacognitive reading strategies, to reading literacy; and 5) the characteristics of the pathways affecting reading literacy differ according to family backgrounds. We propose theoretical and practical recommendations based on these results.