The new "two-child policy",which officially applied in January 2016,will bring another wave of "baby boom" to China.The policy is considered beneficial in adjustment of population structures and maintaining demographic dividend.However,many potential problems will show up since the women who want to have the second child are most likely "older mother" (age over 36 years old),and children rare diseases is one of the evitable facts.Although no explicit definition of human rare diseases,it usually means the diseases have occurrence lower than 1/2000.Currently there are more than 7000 different rare diseases,which make the accumulated occurrences close to 5% of new born population,or 350 million patients worldwide.Even in developed country such as the United States,30% of the children patients cannot survive older than age 5 and almost 35% of the mainly cause of death for children under age 1.Therefore,when a million level "baby boom" coming and maternal ages are high,how to deal with children rare diseases will be a critical problem for government and the public health system.In this essay,a three-step potential solution have been generated,including building national wide newborn screening system,setting prompt treatments systems for diagnosed newborns and increasing the efforts in translational medicine and studies for children rare diseases.