Edible oils are receiving a lot of attention as an alternative fuel for engines as they are renewable and can be used in engines without any major modification. Their properties are closer to those of diesel except viscosity. The main problems of using corn oil in diesel engines are higher emission level and lower thermal efficiency due to higher viscosity and carbon residue compared to diesel. Transesterification of corn oil into biodiesel is the best method to overcome this problem. In the present study we are using corn biodiesel in different blends such as COME10, COME20, COME30, &COME100 are taken for the experiment from this blends COME20 gives good results and for this blend cerium oxide Nano particles is added as fuel additive with concentration of 25ppm, &50ppm. The Performance was improved, and emissions were reduced by using COME20+Ceo2 50ppm.