Method for detecting catalyst deterioration of vehicle

A method for detecting catalyst deterioration in a vehicle, comprising:

• executing, by a controller, a fuel-cut mode of an engine of the vehicle according to an operating state of the vehicle;
• calculating, by the controller, an oxygen storage capacity (OSC) of a catalyst using an oxygen sensor during the executing of the fuel-cut mode of the engine;
• and
• calculating, by the controller, catalyst deterioration based on the calculated OSC,
• wherein the calculating of the OSC of the catalyst comprises:
• integrating an oxygen flow rate from a time when the executing of the fuel-cut mode of the engine begins to a time at which a measured signal from the oxygen sensor installed at a rear end of the catalyst, indicates a lean region of an air-fuel ratio, thereby obtaining an integrated oxygen value;
• and
• setting the OSC of the catalyst as equal to the integrated oxygen value.