This paper analysis the serious imbalances population age structure problems which bring by Shanghai long-term ultra-low fertility，and consider that the fierce competition job and high-cost living is an important reason that many people don’t want to have two children，and the existing maternity-related benefits policy didn’t provide the necessary help for raising two children of the family. Therefore，we need to fully use international experience for reference to encourage fertility effectively，and study and introduce relate policies to encourage families to have two children such as：changing fertility policy，adjusting public opinion propaganda-oriented，advocating the majority of young people have two children，changing the existing welfare policy that encourage late marriage fewer children，and put the part of the cost of infertility treatment into health care，building the infant care network，carrying the welfare matchmaking service that allows unmarried-women have childbearing and so on.