This paper investigates the mixing of the graphene (GR) particles in the polyester (PE) resin by using two different dispersion techniques which are mechanical stirring and sonication method. This paper shows that the mixing method has a significant effect on the corrosive behavior of the coatings. Fourier Transform Infrared Spectroscopy (FT-IR) characterization technique is done to analyze the functional group present and evaluate the graphene/polymer matrix interaction. The FT-IR analysis has successfully done and shows that graphene has grafted onto the polyester resin. The corrosive behavior testing is evaluated by using Tafel testing and immersion test which determines the corrosive properties of the coatings based on the mixing method with three different reaction times starting from 30 minutes, 60 minutes, and lastly 90 minutes. The optimum formulation is found at 60 minutes time reaction by using sonication method. This is due to dynamic features of sonicator that have good quality for dispersion of the graphene into the polymer matrix.