Ignition characteristics of diesel are weak due to higher viscosity and density especially at cold start conditions. So, it is seen that the usage of dibutyl maleate having high content of oxygen as an additive to improve the bad properties of pure diesel is essential and sensible. In this research, a single cylinder DI diesel engine was operated at four different engine loads including 4.12, 9.61, 15.10 and 20.60 Nm to observe and see the influences of dibutyl maleate on performance and combustion characteristics such as heat release rate, in-cylinder pressure, ignition delay etc. and thermal efficiency. It was found that in-cylinder pressure decreased with the addition of dibutyl maleate whereas remarkable increase was observed on pressure rise rate and ringing intensity with fuel blends. ID (Ignition delay) period increased with dibutyl maleate addition into diesel due to lower cetane number while combustion duration shortened with fuel blends compared to diesel. Besides, indicated thermal efficiency decreased about 20.18% and 24.25% with D90DBM10 and D90DBM20 respectively according to neat diesel at 15.10 Nm. Specific fuel consumption increased 5.08% and 8.13% with D90DBM10 and D90DBM20 respectively compared that neat diesel. It was also seen that cyclic variations increased in case of usage dibutyl maleate addition. Test results also demonstrated that HC (Hydrocarbon) and soot reduced while CO (carbon monoxide), CO2 (carbon dioxide) and NOx (nitrogen oxides) raised with the usage of dibutyl maleate compared to neat diesel.