These days, we face of the flood of books published, and data day by day. But there are some trouble to serve the knowlodge and date to the users efficently with a single library. Thats why we think about the way of the cooporation and the connection in modern library for the method of widening the service. As the result of the issue, the establishment for the relation of each library is needed to be done, and the composition of the public library network in same area and limit are also needed. Establishing the library network, the civil life will be much influenced by the service of a library. With the existing ways, library cant arrange data efficently by them selves, and the users are limited. But the library network collect the data with alloting the work to each portion, so it can be possible to gather the specipic data, and the cost caused by needless and overlapped data can be decreased remarkably. Furthermore, the location of the library can be closer than the existing one due to the less cost to maintain the library. As I explained, the convenience of using the library can make an effect on more people to use a library than before.