[Purpose/significance] The paper aims to construct the influence factors model of university libraries’ participation in public cultural service system, and provide theoretical and practical reference for the development of university libraries’ public cultural services. [Method/process] Through in-depth interviews with 26 interviewees from 10 universities, this paper explores the influential factors of university libraries’ participation in public cultural service system using the grounded theory method, and construct its grounded theory model. [Result/conclusion] The influential factors of university libraries’ participation in public cultural service system mainly includes four main categories, namely, the attribution of university and its library, the attribution of government institutions, the attribution of public user, and the other attribution. The attribution of university and its library is the dominant factor, the attribution of government institutions is the guarantee factor, the attribution of public user is the driving factor, and the other attribution is the restrictive factor. On this basis, it puts forward the strategy of university libraries’ deep participation in public cultural service system.