Today biodiesel is another form of fuel for diesel engine because of reducing the cost of petroleum fuel, fast depletion of petroleum stores and the habitat degradation by exhaust emissions from automotive engines. Using Lemongrass oil (LGO) & diesel blends this proposed paper is performed. Direct injection, Air cooled, Mono cylinder engine which is operated in 1500 rpm using Lemongrass biodiesel oil and it's amalgamated with diesel fuel at different ratios (20%, 40% & 60% volume/volume percentage) with different loads. The performance and emission characteristics of Lemongrass oil and its blends are compared with those of diesel fuel. The output for the thermal efficiency of LGO20 is 0.36% upper than diesel fuel and it is higher than other blends. The exhaust gas emissions namely Carbon monoxide (CO), Smoke opacity for LGO20 & unburned hydrocarbon (UBHC) were considerably lowered by 36%, 25% & 14% in comparison with diesel fuel at entire load or full load. The brake specific fuel consumption (BSFC) and the oxides of nitrogen (NOx) emission were raised by 7.6% and 21% for LGO20 and the smoke opacity was decreased by 36% for LGO20 at full load when compared with diesel fuel. © 2023 Elsevier B.V., All rights reserved.