SASW (Spectral Analysis of Surface Waves) is practical and relatively effective in characterizing subsurface ground truth. According to the surface wave in the interesting range of frequency, some criteria for source-receiver configuration are employed and limit the applications. Challenges emerge when SASW is applied to study the surface wave involving multiple modes effect and when the source is near the receiver. In such cases, multiple modes effects and evanescent wave fields are present in array sensing and might weaken the inversion accuracy of pavement subsurface profile. In this work, these issues were investigated and a complex wave number estimation based method was proposed. The complex wave number was estimated by iterative linear exponential fitting from wave field model to response measurements. Evanescent wave for near field and multiple modes effects were focused in the proposed method. Finally, simulated signals from FEA model were processed to demonstrate the algorithm and the results were discussed.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.