Lithium battery pack has the characteristics of high energy storage density and large discharge rate, which is widely used in electric vehicles, energy storage, uninterruptible power supply and other fields. The output voltage of the battery pack varies greatly with temperature, state of charge and other factors. Therefore, it is usually necessary to use a wide input dc/dc converter to convert the output voltage of the battery pack in order to obtain an output voltage with a certain voltage level and accuracy. In this paper, a novel high-precision control method of battery pack output voltage is proposed. The battery pack output voltage level transformation is realized through the reconfigurable battery pack topology, and the high-precision control of battery pack output voltage is realized through the full bridge control circuit. In the proposed method, the working voltage of the full bridge circuit is low, and the output voltage of the battery pack will not affect the working voltage of the full bridge circuit, and the output of any DC voltage level can be realized by a set of system. Firstly, the basic topology and working principle of the reconfigurable battery pack are introduced in detail. Then, the basic principle and implementation process of the proposed high-precision control method are analyzed in detail. Finally, the proposed high-precision output voltage control method of battery pack is simulated and analyzed, and a 1 kW experimental prototype is built to verify it. Simulation and experimental results show that the proposed high-precision output voltage control method can achieve high-precision control of battery pack output voltage.