In this paper, we study the robustness of complex communication networks. We find an effective way to enhance networks robustness by allocating redundancy links among some key nodes. Protecting Key Nodes (PKN) strategy is proposed to improve the robustness of complex communication networks against intentional attack. We show that networks robustness will increase remarkably by allocating a few redundancy links among key nodes and using PKN strategy. Our research on complex communication networks helps to achieve better understanding of communication systems.