Abstract: This study represents the analysis of smoke of biodiesel by using smoke tester. In this article biodiesel is taken as a fuel instead of diesel and quantity of emitted pollutants HC and CO is evaluated by taking different quantity of biodiesel at different load. This work shows how use of biodiesel will affect the emission of pollutants. Diesel Engine is compression ignition engine and use diesel as fuel, in this engine alternative fuel can be used. One alternate fuel is biodiesel. Biodiesel can be used in pure form or may be blended with petroleum diesel at any concentration in most injection pump diesel engines and also can be used in Vehicle, Railway, and Aircraft as heating oil.