Method and relative system for the measurement of haemodynamic indices, said method comprising: acquiring an ultrasound image of at least one segment of an arterial vessel; identifying in said image at least one sample volume; obtaining a time series indicating the blood velocity, or velocity signal (9), in said sample volume and in at least one cardiac cycle; calculating, by means of a processor, a first area (4) equal to the area subtended by the velocity signal (9) between the sample (6) relating to the instant of systole start of said at least one cardiac cycle and the sample (7) of systolic peak; calculating, by means of a processor, a second area (5) subtended by the velocity signal (9) between the sample (7) of systolic peak and the sample (8) relating to the instant of end diastole of said at least one cardiac cycle; calculating the relationship between the second area (5) and the first area (4); selecting a time instant of interest in said at least one cardiac cycle; obtaining the spatial distribution of the velocity in said time instant of interest, or instantaneous distribution of the velocity; identifying the maximum value and the minimum value of the instantaneous distribution of the velocity; and calculating the relationship between the maximum value and the minimum value.