At present, energy saving and emission reduction of marine diesel engines are the two important challenges for development of marine diesel engines. In order to realize diesel methanol compound combustion (DMCC), we have carried out plenty of studies, such as to investigate into combustion in constant-volume combustion chamber, to carry out performance of engine and after-treatment experiments at test bench. The results obtained in these studies showed that the combustion of diesel engaging is reinforced while methanol involving in burning, which is the reason that diesel/methnanol dual fuel combustion (DMDF) has high thermal efficiency. The results from visualization in constant volume bomb illustrated that premixed methanol motivated the diesel premixed combustion. In addition, diesel multiple auto-ignition accelerates the heat release rate of methanol air mixture. The developed DMDF engine can automatically operate and does need to change the mode of operation of engine after it is modified. The emissions from marine engine with the DMDF mode at propulsion cycle are lower than those of engine with diesel mode. The CO emission was 0.003g/kW.h, THC emission 0.009 g/kW.h, NOx emission 5.813 g/kW.h and soot emission 0.06 g/kW.h, which are lower than that of China I emission legislation for marine engine. Compared with conventional diesel engine, since there is a higher ratio of NO2/PM in DMDF engine, it is easier to achieve passive regeneration of diesel particle filter (DPF), and beneficial to prolong the cycle of active regeneration.