Disclosed are an ultrasound system and method for providing a guideline of a needle. The ultrasound system includes an ultrasound data acquirer that transmits an ultrasound signal to an object with a needle inserted thereinto, and acquires ultrasound data corresponding to each of a plurality of ultrasound images by receiving an ultrasound echo signal reflected from the object, a user input unit that receives input information, used to set a point in an ultrasound image, from a user, and a processor that generates the plurality of ultrasound images with the ultrasound data, generates a mask image used to detect an input position of the needle by using the plurality of ultrasound images, detects the input position by using the mask image, and sets a guideline of the needle in the ultrasound image on a basis of the input position and the input information.
