The identification or exclusion between self and other has its safety effects. Identification would bring security and solidarity to a community, and exclusion threat and instability. The safety effects indicate the important roles that national identity plays in the studies of security. From a static point of view, national identity, particularly cultural identity, can explain the formation of international security structure. From a dynamic point of view, identity change of big powers can cause the transition of international security structure. New China has experienced three identity changes since its foundation and has produced considerable safety effects on East Asia and the world. As a great power critical to the world stability and peace, China's future choice of identity should meet the world's expectation by establishing the identity of a 'responsible state' so as to contribute to the world peace and development.