The preliminary objective of the present work is to evaluate the performance and emission characteristics for different CR and engine loads using diesel and Moringa oleifera biodiesel blends as fuel. In the present work mono cylinder, 4-stroke, CRDI-VCR type, CI engine tested using diesel and Moringa oleifera biodiesel blend MB10, MB20, and MB30to investigate the performance and emission behavior of an engine concerning CR at the different loading conditions (0.88, 1.75, 2.66 and 3.5 kW). The experiment was performed at four different CRs 15:1, 16:1, 17:1, and 18:1 at fixed IT 23°bTDCand IP 600 bar. The results of the experiment show that the highest BTE for diesel and biodiesel blend MB30 is reported at 27.26% and 28.26% at the higher CR of the present investigation 18:1 and 100% load condition. The increase in load and CR shows the reduction in the BSFC and BSEC of an engine for all tested fuels and the minimum BSFC and BSEC reported among the entire fuel blend is 0.30 kg/kWh and 12.9 MJ/kWh for MB30 fuel blend at higher CR of present investigation 18:1 and 100% load condition. The minimum emission of CO and HC reported for MB30 fuel at higher CR of present investigation 18:1 and 100% load condition is 0.04 % vol and 8 ppm. In the present investigation, the highest CR of 18:1 and 100% load condition offers the minimum emission of NOx reported as 522 ppm for the biodiesel blend MB20 among entire fuel blends. The results reveal that the NOx emission of the MB20 fuel blend is about 11.97% less than recorded for diesel. The emission of smoke is almost zero for all the fuel blends at the higher CR 17:1 and 18:1 up to 50% loading condition. The highest emission of smoke was observed at lower CR 15:1 and 100% loading conditions for all the tested fuel blends. Moringa oleifera biodiesel blend MB30 shows an enhancement in thermal performance by increasing BTE and decreasing BSFC while improving emission characteristics by reducing emissions of pollutants such as CO, HC, smoke, and NOx.