The essay addresses that, after 30years open and reform policy, with the increasing connectivity with the rest of the world, China has been transforming from a traditional land power to a new type of sea power. This transformation requires a sophisticate and modernized Chinese navy, and more frequent international engagement on maritime security, but it not necessary means that China would follow the model of traditional Western sea power to seek for its regional thalassocracy. The essay argues that, at least in the medium term, even for the long term, Chinas maritime strategy pursues to control its marginal sea and secure its SLOCs. Chinese sea policy is and will be peace-nature and encourages regional and international maritime cooperation. The essay points out, the strategic value of the Indian Ocean for China, an energy-thirsty giant is vital. The vulnerability of the SLOCs for China from the Gulf to the Malacca Straits has drawn a lot of concern of China, and to secure this energy transportation channel has become a significant component of Chinas maritime security strategy. Meanwhile, more intensive participation and wide presence of Chinese Navy and merchant marine in the Indian Ocean will make greater contribution to its Western Development Strategy, and also could be regarded as an indirect strategy to enhance Chinas position on its marginal water dispute with some Southeast Asia countries. The essay suggests that, in the framework of Chinas Indian Ocean security strategy, Pakistan should be regarded as a decisive partner and Gwadar project should lay the cornerstone for this strategy. The meaning of Gwadar port for China is a bridge to reach energy diversity, not a fort to scout and dominate the Indian Ocean. The article consists of four parts, 1. Review of Chinas Maritime Strategy; 2. Chinese Perspective on Sea Power; 3. "String of Pearls" or Line of Life; and 4. Secure SLOCs via Cooperation.