By　successful　implementation　of　electricity　marketization　for　over　20　years,　the　United　Kingdom　(UK)　has　begun　its　3rd　Electricity　Market　Reform　including　capacity　market　to　ensure　that　future　energy　is　secure,　economical　and　low　carbon.　With　drawing　on　the　experience　of　the　UK,　this　paper　enunciates　the　necessity　of　capacity　market,　and　analyzes　the　design　of　capacity　market　in　four　aspects　including　law　development,　operation　stages,　market　participants　and　evaluation　standards.　Based　on　the　first　capacity　market　auction　results　in　the　UK,　this　paper　lists　the　advantages　of　market　design　in　the　prolonging　of　capacity　agreement,　and　its　potential　problems　in　the　UK　including　auction　design　and　the　support　of　storage.　This　paper　also　states　the　developing　ways　of　capacity　market　in　the　UK　covering　capacity　interconnection　and　transitional　arrangements.　In　light　of　comparisons　among　capacity　markets　in　the　UK　and　USA　including　demand,　supply,　market　time　and　ancillary　support,　the　revelation　to　China＇s　future　capacity　market　construction　is　described.　©　2015,　Automation　of　Electric　Power　Systems　Press.