Polyethylene terephthalate (PET) is one of the most important and commercial thermoplastics polyesters which has been in the market since 1977 and it has vastly been used both in industry and household. Through chemical recycling, plastics can be converted into their primary components for use in other chemical processes under especial conditions. Polyethylene terephthalate is a thermoplastic, therefore, recycling by chemical method which converts it into primary components can be achieved. In this study the optimal routes of the existing chemical methods have been chosen. For chemical recycling, acidic hydrolysis is used and PET is converted to terephthalic acid (TPA) and ethylene glycol (EG). Effective factors in the decomposition and the yield such as acid concentration, time, temperature and PET particle size were investigated. Characterization of the products is carried out by FTIR, and the effect of reaction time on PET particles is evaluated by scanning electron microscopy.