Recently, it is concerned with the problem of environmental pollution in the world, and the prevention of exhaust emission is enforcing day by day. The air pollution from vessel is also no exception. The regulation for pollution materials in the exhaust emission from the marine diesel engine will be enforced a few years after. The diesel engine has the high thermal efficiency and can be powered by the various fuels. However diesel, the contents of exhaust gas from diesel engine (Soot dust, NOx, SOx and other toxic substances) cause to the air pollution. The grasp of the exhaust gas characteristics in various operating conditions is important for the development of the exhaust gas purification technology of diesel engines. In this paper, the grasp of the exhaust gas characteristics of the diesel engine is examined. As a result, CO2 and NOx in change of load showed the changing trend generally known, and the influence on the PM measurement value by using opacity meter is clarified.