The NiCo2S4 and NiCo2S4/CNTs composites were synthesized by a one-step hydrothermal method, NiCo2S4, NiCo2S4/CNTs composites were physically characterized by performing XPS, XRD, and SEM, while electrochemical tests were carried out using a three-electrode test system on an electrochemical workstation. The test results showed that the morphology of NiCo2S4 was changed by doping CNTs, the specific capacitance of NiCo2S4 could reach 830 F/g at 1 A/g current density, and the retention of specific capacitance was only 78.3% at 10 A/g current density, while the retention of specific capacitance of NiCo2S4/CNTs composite material reached 78.6% at 10 A/g, and 98.2% at 3 A/g current density for 1000 cycles.