To improve the quality and efficiency of coherent plane wave compounding ( CPWC) imaging for two-layered medium, a frequency-domain beamforming algorithm combined with sign coherence factor (SCF) is proposed. The phase symbol of plane wave data is extracted. And the wave field is extracted by the modified frequency-domain beamforming algorithm. The SCF weighting factor is established by using the field extrapolated phase symbol to weight the plane wave image after beamforming. Results show that, after SCF weighting, the average full-width at half maximum of defects in the time-domain and frequency-domain beamforming images are basically identical, which are 75% and 78% of the time-domain DAS respectively. The signal-to-noise ratio of the frequency-domain images is about 5 dB higher than that of the time-domain DAS. On the premise of the same resolution and signal-to-noise ratio, the imaging efficiency of the SCF weighting algorithm for frequency-domain beamforming are more than 4 times compared to the SCF weighting algorithm for time-domain beamforming. Meanwhile, the high image quality and the low computation complexity are both considered. The proposed ultrasound phased array imaging method is suitable for double medium in nondestructive detection.