Development of non-noble metal catalysts for electrocatalysis is highly desirable. We synthesized flower-like nickel-doped molybdenum disulfide (Ni-MoS2) using a hydrothermal method. The nickel concentration of 6, 11, and 13 at% were added into MoS2. The overpotential of −160 mV for hydrogen evolution reaction at the current density of −10 mA/cm2 and 240 mV for oxygen evolution reaction at + 10 mA/cm2 with Tafel slope of 79 and 102 mV/dec, respectively, is obtained from the nickel doping of 11 at%. The best bifunctional catalytic activities result from the Ni doping of 11 at% which eventually introduced metallic 1 T phase, improved conductivity, and increased electrochemical surface area.