Abstract: In this paper, a concise formula for a mantle structure with low velocity zone is presented, based on the works of Gerver and Markushevich, and McMechan. Although it is merely one of a large number of possible solutions, it is convenient for inverting the travel time data of the upper mantle when the information from LVZ is limited. The velocity structure of the upper-most mantle of the Beijing-Taiwan profile is given as an example.