The current study reports the epoxidation of castor oil (CO) by using hydrogen peroxide as catalyst and formic acid as oxidizing agent. Subsequently bio based polyurethane based base coat was synthesized by using epoxidised castor oil (ECO) as polyol, Isophorone diisocyanate (IPDI) as curing agent and dibutylin dilaurate (DBTDL) as catalyst. The paint formulation with OH:NCO ratio 1:1.2 was optimized. An independent study was carried out employing the mechanical test like cross-cut tape test was carried out to evaluate th paint properties. Morphological and structural studies like FTIR, SEM, HNMR were carried out with the paint formulation. Thermal property studies like TGA, DSC were carried out with the paint. Gloss, weather resistance of the paint was evaluated.