A method and system for ultrasonic fluid spectral Doppler imaging are disclosed. The system comprises: a transmission circuit for transmitting an ultrasonic beam to a detection object; a receiving circuit and a beam synthesis module for receiving an echo of the ultrasonic beam and obtaining an ultrasonic echo signal; an image processing module for obtaining an ultrasonic fluid flow state image of a region of interest in the detection object according to the ultrasonic echo signal, identifying a sampling position in the region of interest, respectively obtaining a Doppler spectrogram corresponding to each sampling position according to the ultrasonic echo signal, and generating position displaying marks for characterizing the sampling positions; and a display for displaying the position displaying marks in the ultrasonic fluid flow state image, and displaying the obtained Doppler spectrogram. The system may simultaneously display spectra of multiple locations on a same time axis.