Astronomy mainly studies specific celestial bodies in the universe, such as the essential phenomena and laws of the sun, black holes, stars and planets. Cosmology focuses on the overall evolution, origin, dark matter, dark energy and global operating balance of the entire universe. Based on the unified theory of infinite hierarchical particles, this paper thoroughly explains all core astronomical and cosmological phenomena from the most fundamental physical logic. It reveals the internal structure, energy mechanism, jet flow, accretion and event horizon of black holes and stars. It also clarifies gravity, galactic rotation, cosmic large-scale structure, dark matter, dark energy and cosmic circulation balance. This theory unifies the underlying operating laws of astronomy and cosmology in one complete logical system.