Earthquake, a major geological hazard, post strong threats to cities and lives. Earthquake not only brings damages during the event, but also causes secondary disasters after it, such as the secondary fires, tsunami, nuclear leakage, and so on. Installing earthquake early warning system (EEWS) is an effective way to reduce the risk of such disasters. While most of the EEWS is based on the Peak Ground Acceleration currently, and this paper analyzes the characters of certain types of vibration and presents a new vibration character sensor which can distinguish earthquakes from other types of vibration from the early part of the P-wave. It reduces the possibility of making false alarm and improves the accuracy of the identification. The components and work principles are given at the last part of the paper. Such a sensor could be used on the earthquake early warning system and as a guide to the post-earthquake rescue work.