Here, we report a one-step simultaneous-construction approach to synthesize N-doped carbon@MoSe2 core/branch nanostructures by heating a mixture of MoO3/PANI hybrids and Se powders in argon atmosphere, without requiring a cumbersome multi-step process or highly toxic reducing agents. It is found that in the construction process, PANI played a crucial role in the reduction of MoO3 and Se to form MoSe2 nanosheet branches, while PANI itself was decomposed and carbonized into N-doped carbon nanorod cores. Interestingly, the coexistence of 1D and 2D nanostructures in the N-doped carbon@MoSe2 core/branch system leads to excellent lithium storage performance, including a large discharging capacity of 1275mAhg−1, a high reversible lithium extraction capacity of 928mAhg−1 and a coulombic efficiency of 72.8%. After 100 cycles, the NDC@MS electrode still delivers a reversible capacity of 906mAhg−1 with a capacity retention ratio of 97.6%. The superior electrochemical properties can be attributed to the unique core/branch nanostructure of NDC@MS and the synergistic effect between the N-doped carbon nanorod cores and MoSe2 nanosheet branches.