To provide a method for regenerating a denitrification catalyst, which is used for regenerating the flue gas denitrification catalyst used in exhaust gas of fuel like coal or heavy oil having high ash content and by which the used denitrification catalyst can be regenerated to have high denitrification efficiency while preventing the exfoliation of a coated layer even when the used denitrification catalyst is not cleaned and to provide a regenerated denitrification catalyst.

This method for regenerating the denitrification catalyst comprises the steps of: coating the used denitrification catalyst containing a denitrification catalyst component and titanium oxide with colloidal titanium oxide and/or colloidal silicon oxide; and coating the resulting denitrification catalyst with a colloidal mixture of the denitrification catalyst component, titanium oxide and/or silicon oxide.