During the construction of public cultural service，the service to vulnerable groups is also very important. To construct the prison library is a key factor of public cultural service system，and also the content of prison development construction. Cooperated with Zigui county prison，Zigui county library establish and complete the Zigui prison library. Moreover，with multiple measures，the prison library is built into a “college within the prison walls” which encourages the prisoners to learn knowledge，settle their mind in reformation，enrich their life，purify their minds，and prepare for the re-employment after they are discharged from prison.