The performance and emission affected by piston catalytic coating have been analyzed in this study. The main contributing factors for improving performance such as load, fuel and speed have been preferred to reduce the emission and improve the performance of an IC engine. These specific standard parameters have been modified with copper alloy coated diesel engine with the aid of design of experiment by Taguchi with grey relational analysis optimization (GRA) method, for improving the IC engine performance and reducing the emissions. The result shows modified copper chromium zirconium (CuCr1Zr) catalytic coated piston produces less emission and improves performance when compared to standard un-coated piston type engine. In this investigation cotton seed oil is used as a bio-diesel and the piston and combustion chamber were coated with copper chromium zirconium material with a thickness of 250 microns. Finally the results of the experiments were compared with un-coated engine and optimized parameters have been identified for catalytic coated modified IC engine using Taguchi with GRA approach.IC engine is the main power source of automotive vehicles. The engine consists of many parts such as piston, cylinder head, cylinder block, etc. Piston and cylinder head are the most important components of IC engine because the power of IC engine depends upon the combustion taking place in combustion chamber. It is located above the piston and bottom of the cylinder head. As the result of the combustion pollutants are produced. Combustion is burning of fuel combined with air. In this chemical process, fuel like hydro carbon combined with oxygen and produces harmful gases leading to air pollution. During the combustion process, oxidization, does not occur properly. So, carbon monoxide is produced, and hydro carbon emission occur due to light load as the lean mixture 1 , So flame speed during the combustion may be too low or in-complete combustion may be occur 2 and hence emission level of HC, CO and NOx in the exhaust gas discharged into the atmosphere through tail pipe is higher compared to copper coated piston type engine. These gases cause many drawbacks to the society. To overcome this problem, catalytic material (copper -chromium -zirconium) is used in the form of 250 -micron coating over the piston crown and combustion chamber walls. The coating of piston and combustion chamber is done using plasma spraying process of thermal spraying technique. Rameshbabu et al. proved that the catalytic coating, reduced the required ignition energy and the flame velocity is increased 3 . Winkler M. F et al. stated that coated diesel engine gives better performance 4 . Jeyakumar et al., state that cotton seed bio diesel can be used as an alternative fuel for control the emissions like CO, HC of a diesel engine 5 .The experimental works were conducted in catalytic coated IC engine. The engine was tested with diesel, cotton seed oil blending with diesel fuel with the ratio of 10% to 20% and by varying the engine performance and emissions p...