Abstract: Britain is the headstream of modern capitalist politic system. The modern systems of parliament, cabinet, two parties can all be traced back to this country. The formation and development of British democratic system resulted from the co-working of various factors. But the unique British national disposition characterized this process with striking British features. Under the influence of the British duel disposition, the formation of its democratic system has walked on a reform road with pioneering and gradualness. In the harmonious alternation of stability and change, the democratic system with British features has formed.