Wave scattering of arbitrary alluvial valleys in a layered half-space to incident plane SV waves was studied using the indirection boundary element method (IBEM). The model was divided into multiple independent closed regions and an open layered half-space region. Scattering wave fields of closed regions were simulated with fictitious distributed loads acting on closed boundaries, and scattering wave field of the open layered half-space region was simulated with fictitious distributed loads acting on open boundaries. Then, the densities of distributed loads were determined according to the continuity boundary conditions. The validity of the proposed method was verified by comparing the results using this method with those using the published method. Numerical analyses were performed for semi-cylindrical valleys with different separation distances and different numbers in an uniformly half-space. The numerical results showed that both surface displacement and amplification spectrum of the observed points are influenced by the above two factors, also frequency and angle of incident SV waves and observation points; the distance between valleys and the number of valleys have a larger influence on surface displacement amplitudes and peak values of amplification spectrum when SV waves propagate with oblique angle; with increase in frequency, the above two factors have a weaker influence on surface displacement amplitudes; displacement amplitudes are influenced severely with decrease in distance between valleys; due to the dynamic interaction among valleys, displacement amplitudes of multiple valleys are bigger than those of a single valley.