In this paper based on analyzing the spectrum of monitoring wavelet and down-going wavelet of zero-offset VSP data we obtain stable interval Q factor. Then is presented improved amplitude spectral fitting and spectral ratio methods for interval Q inversion based on zero-offset VSP data, and the flowchart for processing the zero-offset VSP data. Subsequently, we apply the proposed methods to real zero-offset VSP data, and carry out prestack inverse Q filtering to zero-offset VSP data and surface seismic data for amplitude compensation with the estimated Q value. Inverse Q filter broadened the frequency bandwidth and enhanced the dominant frequency greatly.