Go through the replacement formalities. If the child's hospitalization fund is lost, you can apply for a replacement certificate. The insured person can go through the formalities of replacement certificate with his/her identity certificate to the management office of children's mutual fund in the district where he/she is located, and pay the replacement certificate fee 10 yuan according to the regulations. Children's hospitalization fund insurance is a public welfare project of social mutual aid, which is mainly aimed at local primary and secondary school students and infants, and belongs to an important part of children's basic medical security system.