Background,Motivation and Objective Compressed sensing(CS) allows much lower sampling rate than the Nyquist sampling rate.Recently it has been applied in ultrasound imaging to reduce the data size.In linear acoustics,a plane wave firing is a linear combination of synthetic focusing(SF) firings.Therefore,we propose a novel beamforming technique,named compressed sensing-synthetic focusing(CS-SF),to speed up the acquisition of ultrasound imaging,without compromising the image quality.