A method and a system for displaying efficiency of regenerative braking for an environmentally-friendly vehicle to better educate drivers in regards to their braking habits and hopefully teach them how to improve the fuel efficiency of the vehicle through adjustment of their braking habits while improving the quality of a vehicle by displaying the regenerative braking efficiency in comparison to a total amount of braking during the braking of the environmentally-friendly vehicle on a cluster. In particular, a total amount of braking while the vehicle is braking, and a ratio of the amount of regenerative braking included in the total amount of braking is calculated by a controller. Then the controller determines whether the vehicle is stopped due to braking. Once the vehicle has stopped due to braking, the calculated ratio of the amount of regenerative braking is displayed on a cluster in the vehicle.