Closeby Habitable Exoplanet Survey (hereafter CHES) mission aims to discover Earth-like planets about the nearby stars via high-precision astrometry technique. The major scientific goals of CHES are: (1) to search for terrestrial planets in habitable zones, especially for the Earth-like planet around FGK stars within 10 pc; (2) to discover the planets with orbital periods ranging from 30 days to 10 yrs, and to determine its orbital parameters and the masses; (3) to observe the atmosphere from a wide variety of planets, and to obtain water and methane in the composition, and the structure of planetary atmosphere, which will provide key clues to formation of planets. CHES will greatly contribute to the discovery of the Earth-like planets with microarcsecond astrometry precision in the space, which will definitely deepen our understanding of planetary science, cosmology science, and many other astrophysical fields.
