In the present study, ancient decorative plaster samples from the restoration site of Veppathur temple, Thanjavur district, India has been analyzed. Samples from two different locations of the temple have been taken. Traditional methods such as acid loss analysis and modern instrumental techniques such as, X-ray Diffraction (XRD), scanning electron microscopy (SEM), and Infrared Spectroscopy (FT-IR) were employed in the study. A binder to aggregate ratio has been established from acid loss analysis. Particle of the aggregate are mostly fine in nature, the presence of organics are been identified by organic test that are in agreement with FT-IR analysis. Calcite, calcium complexes, Quartz and Magnesium are present in the form of hydro thermal product are present in the samples. Scanning Electron Micrographs showing the typical hydraulic compounds (CSH and CAH). Amorphous calcium carbonate is found with some perfect crystals of the calcite.