Some of scientists in our country have suggested to launch a dedicated satellite of astrometry in a few years, using astrometry technology with 0.5 micro-arcsecond precision, to search terrestrial planets surrounding about 200 sun-like stars within a distance of about 64 light-years, and to obtain a complete sample of possible habitable planets within the distance. Then, the stars of this sample would be followed up with high precision photometry on large ground-based telescopes or other suitable space-based telescopes to detect the candidates with the transits on host stars, and with high-resolution spectroscopy for these transits to determine whether atmospheres exists on the transit planets and the chemical composition of the atmospheres, especially whether the features of biosignature gases are emerged, and ultimately it be determined whether life is really on the planets or not. If we would be able to finally find such a planet, it will undoubtedly be a great achievement in the sciences.%中国的一些科学家提出，在若干年内发射一颗专门的天体测量卫星，以0.5μas的定位精度，用天体测量方法，对距离约64光年范围内的约200颗类太阳恒星周围的类地行星进行搜索，获得一个在上述距离之内可能具有宜居条件的行星的完备样本；然后就用地面的大望远镜或者其他合适的太空望远镜，对这一样本中的恒星进行高精密度的测光观测，从中找出具有凌星现象的候选者；对这些候选者进行高分辨率分光观测，确定相应行星有无大气层以及其大气的化学成分，尤其是光谱中有无带有生命活动痕迹的气体的特征，并最终确定在这颗行星上是不是真正有生物生存。如果最终能够找到一颗这样的行星，那无疑将是科学上的一项巨大成就。
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