Marine fuel oil quality, the important indicator to operating the marine engine,has been discussed at IMO(International Maritime Organization). Although there has not been a mandatory restriction related to the standard of marine fuel oil quality, except for a sulfur content in fuel oil, the marine fuel oil quality has suggested by ISO 8217 published from IMO(International Maritime Organization). TCC provides the analysis data of fundamental of fuel quality, the evaluation of quality improvement technology of residual fuel and the change of quality of blending fuel in compliance with fuel change-over.