The cycle life of Ni-Zn secondary batteries is largely affected by the dissolution of zinc anode active substances. ZnO/carbon nanotube composites as anode materials are synthesized by physical mixing and chemical filling methods to reduce the dissolution of active substances and improve the electrochemical performance of Ni-Zn batteries. By performing electrochemical testing to the Ni-Zn batteries with anode materials of ZnO/carbon nanotube composites prepared by the two different synthesis methods, we find that the electrochemical performance of the Ni-Zn batteries with anode materials of ZnO/carbon nanotube composites synthesized by chemical filling method is far better than that synthesized by the physical mixing method, with discharge capacity of 410 mA h/g and achievable cycle life of about 600 times. The experimental results pave the way for applications of carbon nanomaterials to the optimal design of zinc anode of Ni-Zn secondary batteries.