In the era of internet, peoples selfexistence pattern, social relation pattern and interaction pattern among subjects appear in a new way in the network society. And internet ideology becomes a new form of daily life. Cyberspace, as the fifth space with distinct features, has become the main battlefield of national ideology confrontation and discourse power id the main core of the fight. Thus, the security of network ideology discourse is evolving into a global security issue, which has been a new frontier of national security. Today, China has to be faced with the contemporary challenge which derives from the unbounded virtualization of network society. On the one hand, the United States, as a representative of western society, controls the right of making network and the right of making information and extrudes the discourse space of socialist main ideology. On the other hand, negative information of network amplifies while the guidance of network media weakens, which makes the impact of main ideology discourse power be weakened. Therefore, firm mastering of network ideology discourse power is the new task of China to maintain ideology security.