An ultrasound system, which operates at a plurality of diagnostic modes, includes: an ultrasound probe configured to transmit an ultrasound signal to a target object and receive an ultrasound echo signal reflected from the target object a power supplying unit configured to supply a power of different voltage levels according to a diagnostic mode to form a transmit pulse signal to be supplied to the ultrasound probe and a transmitting unit connected to the ultrasound probe and the power supplying unit, the transmitting unit being configured to constantly supply the power in a first voltage level at a transmission time period of an ultrasound signal and vary the voltage level of the power from the first voltage level to a second voltage level based on a predetermined waveform at a transmission idle time period.
