引用Zhang和Tindle的更有效深度的概念；将Chapman提出的浅海Pekeris波导的海底（实）有效深度近似，推广到复有效深度近似，其实部和虚部分别反映平面波反射的相位变化和能量损失。通过对比计算表明：由复有效深度近似构成的均匀声场，能反映对应于小掠角的低号简正波的声学特性，有效地计算浅海远距离声场．有关结论可以推广到包含两层软固态海底的波导之中． The concept of more effective depth of Zhang and Tindle is introduced. The submarine (real) effective depth approximation proposed by Chapman for shallow-water Pekeris waveguides is extended to the complex effective depth approximation. The real part and the imaginary part respectively reflect the phase change and energy loss of plane wave reflection. The calculated results show that the uniform sound field formed by the complex effective depth approximation can reflect the acoustic characteristics of low-profile simple waves corresponding to a small sweep angle and effectively calculate the long-distance sound field in shallow water. The conclusion can be generalized to waveguides that contain two layers of soft, solid seabed.