With the success of acquisition and processing of multiple component seismic data, people are trying to get more and better information from multicomponent seismic data to characterize the reservoir. Mapping of V P /V S provides important information. Due to the significant difference of frequency spectra of PP and PS seismic volumes, we designed the band pass filter based on the frequency spectrum of PS seismic volume, which has a narrower frequency band and lower dominant frequency, and applied the band pass filter to PP seismic volume. The quality of V P /V S map from PS and filtered PP seismic volumes was significantly improved compared with the quality of V P /V S map from PS and unfiltered PP seismic volumes. Meanwhile, the error from surrounding formations was analyzed because we usually can not get reliable reflection pick from the target formation and have to interpret those coherent events from surrounding formations. The error analysis was based on the interpreted model, and the result was that the effect from surrounding formations was negligible if the velocities of surrounding formations did not change much laterally. The assumption could be satisfied in most cases when we considered the geological background. If the velocities of surrounding formations change significantly, we can limit the area to interpret the pattern of V P /V S to improve the reliability of this method.