On January 15th of 2020, the American Association for Library Service to Children issued a white paper entitled Engage, Cultivate, Provide, Assess: an Outreach Model for service Children and families in which four service models were put forward based on investigation of the current situation. After an interpretation of the paper and an analysis of the characteristics of American extended services, Suggestion were put forward here for our public libraries to develop in extended services, including remodeling concept, expanding social  participation, and putting more attention to service evaluation.