The present study “Archaeoastronomical study of the Megalithic Monuments in Andhra Pradesh” tries to explore how the Megalithic people followed the astronomy with naked eyes, how they built huge structures without any help of scientific equipment, through the archaeological evidence gleaned from Megalithic monuments and reconstructs the Megalithic astronomy and geometry of Megalithic people in Andhra Pradesh region. It is purely field-based work and personal observation of heavenly bodies from sties. We can study the history with the help of archeological remains of tangible and intangible material but could not read their heart. Observing and recording the position of the celestial bodies like the Sun, the Moon, the Planets and the Constellations and heavenly changes was a major step of intellectual growth of ancient man. This study tries to explore megalithic people’s astronomical observations, based on the monuments that they have constructed. The study shows how different groups of people interact with the cosmos, and it allows us to look at the development and formation of scientific and religious believes relating to cosmos.