Earth simulator is a parallel vector super-computer which deve loped by National Space Development Agency of Japan(NASDA)and Japan Atomic Energ y Research Institute(JAERI)and Japan Agency for Marine-Earth Science and Technol ogy (JAMSTEC).Understanding and forecasting high-impact phenomena in the atmosph ere and ocean,global warm,crust.The performance of Earth Simulator,birth of the Earth Simulator,research contents of five groups which are Atmosphere and Ocean Simulation Research Group,Solid Earth Simulation Research Group,Multiscale Simul ation Research Group,Advanced Perception Research Group and Holistic Simulation Research Group,research projects and collaborations are introduced.At last,usage details details of the Earth Simulator and sustained performance of actual appl ication are introduced.