Abstract: According to the difficulty of trajectory measurement with high accuracy and high frame rate for UVMT(Underwater Vertical Motion Target) in transient motion, an acoustic localization model using multi-stations in the seabed with the acoustic beacon was presented, and solving algorithm based on Gauss-Newton method was derived,which was proved to be satisfying the local linear convergence condition. The results of numerical simulation and accuracy analysis indicated that station location errors, sound velocity errors and signal time delay estimation errors were propagated to position parameters through measuring slant ranges, and this process was effected by geometry of receiving array, relative position of the target and acoustic constraint conditions. Furthermore, the vertical measuring ability was improved by adding a surface station on the basis of coplanar multi-stations in the seabed. A full-area coverage accuracy estimation was applied and its detailed distribution characteristics were available. Demonstrated by a sea area of 1 km × 1 km coverage and 60 m in depth, in the condition of 14-receivers array which was composed of 13 seabed stations and 1 surface station, the range of UVMT motion depth was 35-60 m, the average RMSE(Root Mean Square Error) in the x, y and z direction was 0.30 m, 1.47 m and 0.34 m respectively. The present work provides a technical approach for UVMT localization, which is useful for designing the measuring system.