Abstract: After being released from the vessel, the OBS begins falling towards the seafloor. There is also lateral drift during its falling. Therefore, before any further processing to be done, it was indispensably needed to relocate OBS. The first arrival time was commonly used in relocating technology, especially for deep water. The traditional method was using mass grid computing of the LMO of the first arrival time to find the grid whose LMO is flat. It is a work of time consuming In this paper, we made a series of direct wave time modeling for several cases of relocation. It is a work of time consuming. Based on the review of the traditional method, we presented a new cross-relocating method to estimate the drifting distance in this paper. The new method was used to relocate the OBS in 2012. The results were satisfactory. Comparing to the traditional method, the computing work load was much reduced.