A water/oil two-phase solution strategy has been developed for the synthesis of various β-Co(OH)2 nanostructures. More importantly, two different morphologies of β-Co(OH)2: mesoporous nanowafers and nanohexagons were successfully obtained through one reaction. Furthermore, the special mesoporous of β-Co(OH)2 nanowafers and nanohexagons exhibited excellent electrochemical hydrogen storage capacities and cycling stability. The maximum capacity reached 265.9 and 215.7 mA h g?1 at room temperature, respectively. After 70 cycles, the discharging capacities of the electrode still remain above 218.2 and 175.4 mA h g?1, which indicates that the as-prepared mesoporous β-Co(OH)2 nanowafers have a strong resistance against oxidation and corrosion. These results indicates that the mesoporousβ-Co(OH)2 nanowafers and nanohexagons may be potentially applied for electrochemical hydrogen storage.