TWC(Three-Way Catalyst) was synthesized by controlling trace precious metal and coated on ceramic monolith substrate using conventional method. Especially, synthesized TWC consists of simple catalyst system. differently from conventional scheme. It means that we use two or three trace precious metal. The catalyst is analyzed by FT-IR for catalytic activity of CO, NO and C₃H?. As the result, light-off of each detrimental gas shows the good activity.