This Paper focused on the Citronella oil based bio diesel which is important renewable and alternative fuel in future. Citronella oil is used as an input for biodiesel production via transesterification. Diesel fuel is much higher use than any other gasoline fuels because diesel engines have many adaptabile domestic uses like small irrigation water pumbing systems, light weight four/two seated auto cab and car engine small electricity generators etc. Citronella biodiesel fuel properties are observed and tested in the fuel testing laboratory with standard procedure. Then an experimental set up is construct to study the performance of a small Kirloskar Diesel in the internal combustion engine by using different blends of Citronella Oil based biodiesel under different Operation Conditions. We have to determine the optimum performance of this citronella biodiesel. NOx emission from the test engine can be measured by chemical luminescent detector type NOx analyzer. © 2006-2014 Asian Research Publishing Network (ARPN). © 2014 Elsevier B.V., All rights reserved.