Abstract: Frequency-domain ultrasound imaging based on Fourier transform has higher imaging efficiency compared to traditional time-domain ultrasound imaging, but its resolution is lower, and image quality needs improvement. Based on angular spectrum theory, a phased array ultrasound Fourier plane wave coherent imaging (FPWCI) method was proposed. By performing wavenumber expansion in the frequency domain, spectral aliasing could be effectively avoided, diffraction limit information could be fully utilized, and the spatial resolution of images could be improved. Simultaneously, a frequency-domain coherent weighting factor was proposed, which effectively improved weighting efficiency and reduced artifact noise compared to traditional weighting. Plane wave, Fourier ultrasound plane wave, Fourier plane wave coherent, and plane wave coherent imaging methods were used to detect arc-shaped defect test blocks and were verified on rail test blocks. The results showed that the proposed phased array ultrasound imaging technique outperformed traditional time-domain ultrasound imaging in both imaging efficiency and quality, and it had significant application potential in the field of engineering nondestructive testing.