Abstract: The pension system in German started in 1880s. Until 1950s, a series of pension reforms were enacted continuously because of the change of social environment after the World War Ⅱ. Various pensions were settled for different purposes, from the purpose of political stability, to encouraging labor mobility and relieving unemployment. Until the end of the 20th century, the sustainability reforms begin to balance more and more complicated economic environment and public living standards. For the content of reforms, changes happened to form financing strategy, pension calculation methods and also ages adapted to policy. In terms of consequences after reforms, the article includes the change of retirement ages, old-age employment and public finance expense including relevant ratios. In the micro level, the article puts together different studies on public reactions towards new pension system, and different social groups reactions under the current pension system. Based on the above, this article analyzes the expected retirement ages under the influence of new pension system, and provides available references for China.