The cobalt hydroxides were in situ synthesized via hydrothermal method with carbon fiber derived from cotton as substrate using cobalt nitrate as cobalt precursor and hexamethylenetetramine as precipitation agent. The morphology and structure of the materials were characterized by scanning electron microscope(SEM), X-ray diffraction(XRD) and IR spectra, respectively. The electroch-emical performance of the samples was analyzed by electrochemical tests such as cyclic voltammetry, galvanostatic charge and discharge and AC impedance. The XRD and SEM results show that, the obtained cobalt hydroxide grown in situ on the carbon fiber substrate is flower-like and α-phase. The electrochemical performance tests display that the specific capacitance of the flower-like cobalt hydroxide is 650 F/g at the current density of 1 A/g, and the retention rate of 67% can be kept with the current density of 10 A/g. The above results illustrate that the flower-like cobalt hydroxide has excellent electrochemical performance, mainly due to its unique structure and morphology, which significantly improves the stability of the electrode material, the diffusion rate of ions and the transport efficiency of electrons.