According to the Resolution of Administrative Supreme Council in 1379, all public sector agencies are obliged to design and implement suggestion system. This article tries to evaluate this system based on the CIPP Model in the Yazd Branch of Tele Communication Company. Based on this model, four dimensions of suggestion system – Context, Input, Process, and Output - were evaluated to find and improve its deficiencies. The results of this research indicate that the adaptability of the suggestion system with the situational variables in this public company and the desirability of its process are at an average level. Meanwhile, its effectiveness and its input desirability are under expectation. Therefore, it is necessary to enhance its degree of success by modifying environmental conditions and doing managerial actions.