The nanoparticles diesel additives played a major role in enhancing diesel performance by improve its efficiency and alter the emissions of CO, NOx and HC including several hazardous air pollutions. Zinc oxide nanoparticles (ZONP) is used in diesel engines which blended with diesel by using ultra sonicator and a mechanical homogenizer to achieve good dispersing. Five concentration of ZONP are studied in this study. To demonstrate and access the enhanced performance of the nano-diesel blend a comparison of fuel consumption, brake power and engine efficiency with base diesel are made. The addition of ZONP promote combustion by increasing engine performance and reducing the emissions. To evaluate the impact of ZONP on engine performance and environment, several experiments performed on the diesel engine at 1400 rpm which is kept constant throughout the experiment with different range of loads. The results show clearly that by adding the nanoparticles, namely ZONP into the diesel fuel has significant improvement of high the brake thermal efficiency (BTE) and low Brake Specific Fuel Consumption (BSFC) as compared to diesel. Also, the average reduction in CO is 33% for high ZONP concentrations and applied high loads while average increases in CO2 is 8%, and NOx is 33% and more for high ZONP concentrations and applied high loads compared to pure diesel. Furthermore, 100% eliminated HC is observed when compared to pure diesel at different loads.