New Zealand superannuation system of universal state pension and private retirement saving which tax policy transformed from tax-neutral（1987-2007）to tax-incentive is unique among developed countries. New Zealand provides adequate and largely satisfactory basic incomes protection for all older people，abating inequality with high degree of simplicity and lowest fiscal costs. This paper examines how New Zealand was able to achieve this system and sustain it，asking why New Zealand still wholly adheres to its traditional two pillars and does not converge to the mainstream of three pillars. The welfare philosophies and the initial organizational set-up have affected the cognitive views of later policymakers. Anglo-American welfare philosophies，persistent generosity of basic pension scheme and booming private retirement saving all together decide the “two legs” way of New Zealand pension. The advantages and practical experience of New Zealand pension system provides an alternative model to the new type rural social pension scheme in China.