Abstract: Optical fiber distributed acoustic sensing (DAS) technology makes downhole-surface joint exploration more efficient because of its high temperature, high pressure resistance, and high-density whole-wellbore acquisition.It has been widely used in well-driven parameter estimation and near-well imaging, but it currently faces technical problems such as low signal-to-noise ratio, difficult wavefield separation due to one-component (1C) data, inhomogeneous illumination, and unsatisfactory imaging caused by sparse shot points.In this study, many issues were investigated, such as the acquisition quality and its influence on the processing of DAS VSP data with cemented fiber, separation of DAS 1C wavefield, well-driven parameter extraction, multiple reflection analysis, and technical advantages and weakness of 3D-VSP imaging.A series of technical achievements were presented, such as efficient first break picking, refined well-driven parameter extraction, high-fidelity 1C wavefield separation, and extended bin VSPCDP imaging.It has been pointed out that the emphases would achieve high S/N data from high-density raw data, further improving the wavefield separation fidelity, and overcoming the effect of shot point sparsity as much as possible in the processing, realizing 3D-VSP precision imaging, and finally achieving joint borehole and surface imaging.This understanding has very positive guidance for DAS joint VSP and surface seismic exploration in the future.