This paper discussed the algorithms of dispersion analysis for both high density surface wave survey and array microtremor observation and derived a unified expression of objective function for dispersion analysis. This unified expression made it possible us to joint analyze the two kinds of exploration data to obtain dispersion data from high frequency to low frequency, and estimate the shear wave velocity structure from the surface to depth by dispersion inversion. This method was applied to the geo-investigation of Songjiang Ancient Wall. The survey result provides a subsurface structure model to 40 m deep for earthquake response analysis, and proves that this method is simple and rapid, with good resolution and deep survey depth.