Transition metal sulfides gain much attention as electrode materials for supercapacitors due to their rich redox chemistry and high electrical conductivity. Designing hierarchical nanostructures is an efficient approach to fully utilize merits of each component. In this work, amorphous MoS2 is firstly demonstrated to show specific capacitance 1.6 times as that of the crystalline counterpart. Then, crystalline core@amorphous shell (Ni3S4@MoS2) is prepared by a facile one-pot process. The diameter of the core and the thickness of the shell can be independently tuned. Taking advantages of flexible protection of amorphous shell and high capacitance of the conductive core, Ni3S4@amorphous MoS2 nanospheres are tested as supercapacitor electrodes, which exhibit high specific capacitance of 1440.9 F g−1 at 2 a g−1 and a good capacitance retention of 90.7% after 3000 cycles at 10 A g−1. This design of crystalline core@amorphous shell architecture may open up new strategies for synthesizing promising electrode materials for supercapacitors.