Zinc-ion batteries (ZIBs) are widely studied as a potential alternative to lithium-ion batteries. However, the low capacity and poor cycling lifetime of the cathode materials limit practical application. Herein, the MoS2/Ni3S2 heterostructure is constructed on Ni foam by a one-step hydrothermal method. Owing to the three-dimensional perpendicular arrays of nanorods with a large surface area, fast electron transfer rate, and synergetic effects rendered by the different constituents in the materials, the assembled quasi-solid-state MoS2/Ni3S2 (MNS)//Zn battery shows a high capacity of 1.42 mA h cm−2 (at 15 mA cm−2), excellent cycle stability (84.6% after 6000 cycles at 80 mA cm−2), outstanding energy density (2.38 mW h cm−2), and maximum power density of 99 mW cm−2. More importantly, the MNS//Zn battery continues to function normally after bending at some angles and even being punctured. The results demonstrate that MoS2/Ni3S2 is a suitable cathode for alkaline zinc battery and has huge potential in flexible devices.