An eco-friendly vehicle and a hill descent control method therefor are provided to enable stable driving on a downhill road. The method includes detecting a downhill road inclination based on a request for hill descent control and determining an average inclination and an inclination variation width based on the recognized downhill road inclination. First braking force of a main braking source from a motor and a hydraulic pressure brake system based on the average inclination and the inclination variation width, and second braking force of an auxiliary braking source from the motor and the hydraulic pressure brake system for each driving wheel based on a target speed set with respect to the hill descent control and a speed of each driving wheel are determined. The first and second braking force are output by a corresponding braking source from the motor and the hydraulic pressure brake system.