The supply-side reform of public culture is the way to solve the problem of "supply and demand dislocation" in the field of public culture. The services of public library have the characteristics of common and public welfare. So the use of "public service +" logical framework can provide new ideas for the supply-side reform of public library.The "public service +" logic of the supply-side reform of public library is to improve the service system of the public Library from the angle of resource allocation and value promotion, through "service content +" "service level +" "supply main body +" "public value added +" etc. to satisfy the expression of the service demand of public library.