【Purpose/significance】The evolutionary model of young children's reading loss behavior in library based on S-O-R model

can facilitate the library to implement personalized recommendation and user churn forecast for the young children group in the future.【Method/process】The grounded theory is used to encode and analyze the interview data of young children's parents and extract the los⁃ing user labels of young children's reading from four aspects: young children's loss factors, psychological changes, loss behavior and basic attributes. Proposing a method to construct the user portrait model of young children's reading loss group in library to classify the loss of users into four types: resource sensitive, environment sensitive, external influence and objective restriction.【Result/conclusion】Based on the S-O-R model, proposing the evolutionary model of young children's reading loss behavior in library to clarify the rela⁃tionship among influencing factors of user loss, user psychological change and user loss behavior, so as to provide reference for the li⁃brary to promote the optimization of library reading services for young children, and promote the construction of civil reading.【Innova⁃tion/limitation】Promote the optimization of library reading services for young children, and promote the implementation of national reading construction. The disadvantage is that the extraction of reading loss labels for young children is indirectly obtained through in⁃terviews with parents of young children, which is not comprehensive, and more in-depth research on the ontology of young children is needed.