In this work, high density polyethylene (HDPE) with organophilic treated clay, Cloisite 15A, and a compatibility agent, a HDPE grafted with maleic anhydride (PEMA) were prepared by melt blending using twin screw extruder with two step process. The influence of the presence and different concentrations of the compatibilizer on the structure, melt flow index, and the gel percentage of the nanocomposites has been evaluated. X-ray diffraction studies showed that there was no intercalation of the clay layers in the absence of compatibilizer, while an obvious increase in d-spacings was observed when increase concentrations of the compatibilizer in samples, but at 20 wt% of compatibilizer was saw slightly reduce in d-spacings the between silicate layers. Scanning Electron Microscope (SEM) studies on the surface coating nanocomposite showed that coverage provided under pre-heat for 1 minute at a temperature 100?, voltage spraying 60 kV, duration heat technique for 30 minutes at a temperature 200?, surface is smooth and without deficiency. X-ray diffraction studies on nanocomposite coating showed slightly increase in d-spacings the between silicate layers. Flexibility and strength of adhesion increased with increasing compatibilizer concentration , but at 20 wt% of compatibilizer, not change in the mechanical properties. Coating containing 15 wt% compatibilizer showed the highest corrosion resistance to the Fog salt water. Keywords: Montmorillonite, high density polyethylene, nanocomposites, powder coating, Electrostatic spray