An ultrasonic imaging system for generating an ultrasonic image of a motion status of an object according to at least an ultrasonic motion signal generated by detecting the motion of the object is provided. The ultrasonic imaging system includes a demodulation module, an analog sub-array beamformer, a filter, an analog-to-digital converter and an image processing module. The demodulation module receives and demodulates the ultrasonic motion signal so as to generate and send at least a demodulated signal. The analog sub-array beamformer receives the demodulated signal, generates and sends an analog sub-array beam signal according to the demodulated signal. The filter receives and filtering the analog sub-array beam signal. The analog-to-digital converter converts the analog sub-array beam signal filtered by the filter into a digital sub-array beam signal. The image processing module receives the digital sub-array beam signal so as to generate an ultrasonic image of the motion of the object.
