To improve the defect detection ability of heavy thick wall components, a method that combines the compounding diverging wave imaging (CDWI) and circular statistics vector (CSV) is proposed in this article. Based on the virtual source technology, the method realizes a wide range of deflection wavefront emission of full aperture array elements by transmitting delay to increase the acoustic energy of wavefront in depth and width propagation direction. To effectively improve the detection ability outside the effective coverage area of aperture, the quality index of defect echo image is further increased by combining CSV in coherent combination process. For the Φ2 side drill holes with the lateral distribution which exceeds the coverage range of the probe aperture by 20 mm, and the longitudinal depth that is between 2~ 3 times size of the probe aperture in the aluminum block, the amplitudes of the SDH echoes of the proposed method are about 17. 5~ 18. 5 dB and 10. 6~ 14. 8 dB higher than them of the plane wave imaging, respectively