Abstract：A refined sub-regional time domain reciprocal procedure in precise step-by-step integration scheme dealing with the problem of wave scattering in unbounded space with inhomogeneous geology or irregular geography is proposed based on the damping solvent extraction method (DSEM)，where the radiation condition of the unbounded domain is automatically satisfied，and the frequency-dependence or convolution integral，as required in the other algorithms in time domain，are synchronously avoided. The numerical implementation of the method is given in detail and is suitable for the case of complicated cavity geometry. The wave scattering at the boundary of cylindrical cavity in 2D infinite space with the horizontally incident SV-wave conditions is simulated to validate the proposed method. The numerical results are compared with the solutions obtained by Cloning element method and analytical formula. It has been shown that the proposed procedure is of good accuracy and feasibility，especially for middle and low frequency ranges in seismic analysis.
