Objective To in-situ fabricate self-collected Ni(OH)2 supercapacitor electrode materials with excellent capacitance and good cycle stability by a facile, cost-effective and green method. Methods The hydrothermal treatment of Ni foam was performed in a 15wt. % H2O2 solution at 180 ℃ for 24 h to in-situ fabricate Ni(OH)2. The morphologies, phase composition and electrochemical performance of the as-prepared Ni(OH)2 electrode material were characterized. Results The β-Ni(OH)2 hexagonal platelets with the side lengths of 400 ~600 nm and the thickness of ~200 nm were obliquely laid on the Ni foam at high densities. The electrode demonstrated excellent capacitance (2534 F/ g at a scan rate of 1 mV/ s) and good cycling stability (91% capacitance retention after 1000 cycles at a scan rate of 50 mV / s) in 2 mol / L KOH aqueous solution. Conclusion The fabrication method developed here was facile, cost-effective and green. The as-prepared binder-free, self-collected electrode material exhibited remarkable electrochemical performance with high specific capacity and good cycling stability.