System for controlling failure of environment-friendly vehicle

A system for controlling a failure of an environment-friendly vehicle is provided to which a highway driving pilot (HDP) system is applied. The system includes a vehicle control unit (VCU) controller that operates a driving motor, an integrated electric booster (IEB) controller that operates IEB for controlling a brake of the environment-friendly vehicle and generate a request to the VCU controller for regenerative braking, and an HDP controller that calculates a required deceleration of the environment-friendly vehicle based on the situation around the environment-friendly vehicle, determined through cognitive control sensors applied to the environment-friendly vehicle. The HDP controller transmits the required deceleration to the IEB controller. At least one of regenerative braking of the driving motor or braking through the brake is performed based on a type of a fault message output by the IEB controller or a failure in communication between the HDP controller and the IEB controller.