A method of maintaining diesel particulate filter (DPF) regeneration for improving durability of a DPF, may include determining, by a controller, whether a vehicle enters an idle state during the DPF regeneration, controlling, by the controller, a concentration of oxygen introduced into the DPF to be equal to or less than a first reference value when the vehicle enters the idle state, and performing, by the controller, a regeneration process until a soot mass in the DPF may be equal to or less than a target reference value.