The pressure and horizontal velocity signals of a vector hydrophone are adopted together in the time-reversal (TR) processing, which can be used in the passive localization of the underwater target. In order to model the replica field, an improved cost function of the Bartlett estimator is offered. Based on the single floor seabed model, the sensitivities of the geoacoustic parameters are analyzed. It was found that, the bottom density and bottom attenuation are insensitive to the proposed Bartlett estimator, and the sound speed of the seabed and depth of the ocean are sensitive parameters. Further, the performance of TR localization shows robustness to the mismatch of the insensitive parameters. Hence, only the sensitive parameters need to be calculated in the geoacoustic inversion. In order to demonstrate the proposed geoacoustic inversion method and the passive TR localization technology, an experiment of a vector hydrophone was carried out in the lake. Using the optimized parameters obtained from the inversion, the passive TR localization of the target was successfully realized