Guaran was transformed into grafted polymer using polyvinyl acetate monomer. The grafting was initiated through the formation of free radical centers on the polymer backbone by oxidation of guaran with cerium (IV) in nitric acid medium. The degree of grafting was varied by using varying amount of acryl amide vinyl monomer. The rheological properties of the guaran grafted poly vinylacetate copolymer have been studied by varying the degree of grafting, time, concentration, temperature, spindle number and shear rate. Thermal Characteristics of the guaran-grafted polyvinylacetate was studied using thermogravimetric analysis under nitrogen atmosphere. The prepared copolymer was characterized by FTIR.