Uniform NiS nanowhiskers have been prepared via a hydrothermal reaction between NiCl2.6H(2)O and Na2S2O3 in the presence of surfactant of C17H33COOK (potassium oleate). The images characterized through XRD and TEM indicates the morphology of hexagonal NiS is uniform nanowhiskers with an average diameter of 80 nm and length in micrometer scale. The formation mechanism and surfactant effect were discussed in details.