The present invention relates to a high performance SCR catalyst system for solving problems of an SCR catalyst system to be applied for the treatment of an exhaust gas of a marine diesel engine, particularly, a turbocharged engine, wherein a catalyst module for removing SOF components is attached to the back end of an engine, and a SCR catalyst module is successively provided downstream thereof, thereby enabling effective removal of nitrogen oxides. In addition, SOF components are decomposed at a relatively low temperature of 200 DEG C or lower, thereby solving problems such as a decrease in SCR catalytic activity due to the accumulation of SOF components, which are a sticky liquid mixture, on the surface of an SCR catalyst, and clogging of a honeycomb-type support channel due to the stickiness of SOF components.