Due to environmental safety, limitations on the exhaust emissions of the internal combustion engine have become more and more severe. The important pollutants from diesel engine are oxides of nitrogen, particulates, hydrocarbon and carbon monoxide. It was found from the literature that various in-cylinder combustion treatment methods, such as ceramic coating on the piston, diamond-like carbon coating on the piston, zirconia coating on the piston, and various ceramic coatings on the cylinder head and liner, have been used in diesel engines to improve the performance and reduction of various emissions. In this present investigation, an attempt has been made to study the performance and emissions from a direct injection diesel engine using nano catalyst nano coated pistons. The pistons were coated with copper and cadmium nano catalyst at the top of the piston using plasma spraying techniques. Engine performance and emission characteristics were compared with baseline engine. It was observed that there was significant improvement in the performance and reduction of various pollutants emitted from the diesel engine.