The IMO’S 72nd MEPC meeting proposed the goal of reducing greenhouse gas emissions by up to 50% by 2050. Thus, various eco-friendly fuels are proposed as alternatives, but there are also various issues that need to be tackled, such as storage stability and supply system issues in a special environment a ship has. Therefore, in this study, the possibility of reducing greenhouse gases was analyzed by applying MGO as an alternative to boilers operated with HFO, a Bunker-C series. As a result, the exhaust gas temperature decreased by about 11.54% from 316.9℃ to 280.3℃, and the amount of oxygen content increased by about 0.38% from 6.27% to 6.65%. It can be seen that carbon monoxide can be reduced by about 45.28% by simply converting fuel from 45.29 ppm to 24.78 ppm, and carbon dioxide, which is a typical greenhouse gas, can be reduced by about 0.49% from HFO by 11.08% to MGO by 10.59%. This means that some greenhouse gas reduction is possible only by shifting between ship fuels that satisfy ISO-8217, but since there are limitations to achieving strong carbon neutrality proposed by IMO, it will be necessary to actively utilize the use of various alternative fuels in the future.