Abstract: Finite size of an earthquake rupture, one of the key concepts in modern seismology, has significant implication for the design of an earthquake early warning system （EEWS）. We discussed this issue by scenario earthquake cases, arguing that an EEWS has the potential to make much greater contribution to the reduction of earthquake disasters which is far beyond the expectation in the view of traditional seismology. The discussion deepens the present understanding of the EEWS design which does not aim at a homogeneous deployment, stressing that near-fault denser earthquake early warning station deployment may make the EEWS much more effective during great earthquakes.