A cruise control system capable of: determining, by a controller, whether the vehicle is in a cruise mode-on state; determining, by the controller, an operation mode of the vehicle selected by a driver; and when it is determined that the vehicle is in the cruise mode-on state, performing, by the controller, cruise control of the vehicle for the operation mode selected by the driver, and a method therefor. Herein, the operation mode includes an eco mode which performs driving control prioritizing fuel consumption reduction.