There is provided an ultrasound system, which includes an ultrasound diagnostic unit for transmitting ultrasound signals to a target object in a periodic motion and forming ultrasound images based on receive signals reflected from the target object, the ultrasound diagnostic unit further being configured to provide reception times of the receive signals corresponding to the ultrasound images; a first storage unit for storing the ultrasound images provided from the ultrasound diagnostic unit together with the reception times of the receive signals; a cycle setting unit for setting a cycle of motion of the target object; a processor for selecting the ultrasound images within a specific cycle among the ultrasound images stored in the first storage unit based on the reception times of the receive signals corresponding to the ultrasound images and start and end times of the specific cycle provided from the cycle setting unit, the processor further being configured to form an equal number of ultrasound images within each cycle based on the number of the selected ultrasound images; and a display unit for simultaneously displaying the ultrasound images within each cycle.