The precise validity of cosmological principle and general relativity is the cornerstone of the standard model of modern cosmology (ΛCDM) and is the logical presupposition for the existence of dark energy. Cosmologists usually assumed that the general relativity is the perfect law of gravity from small to large scales, which has been tested by many tests in Solar system and a few cosmological tests. The cosmological principle assumes that the universe is homogeneous and isotropic on a sufficiently large scale. However, several possible challenges to cosmological principle was reported in recent years. In this talk, we will introduce our progresses on the tests of cosmological principle and related works on the models and properties of dark energy, which is the main explanation for cosmic acceleration. At the same time, we will present our recent works on the observations of interstellar molecules, which is the prelude of origin of possible extraterrestrial life.