Provided is a method of marking a diffusion boundary of medicine, the method performed by an ultrasound apparatus and including operations of obtaining first B mode image data and first Doppler data about a target object to which the medicine is injected； detecting a first area of the target object from which the first Doppler data is obtained； determining a first diffusion boundary of the medicine, based on the first area； and marking the first diffusion boundary of the medicine on a B mode image that is generated by using the first B mode image data.
