An excess of discipline turns to abuse. When parents exercise their discipline power towards children, it will lead to the physical harm of the children. Since abuse has a great effect upon children's personality and the core of parental rights is for children's good, state can protect children from abuse by limiting parental rights; namely, states can limit parental rights to guarantee children's right not to be physically harmed. However, another problem appears: though the purpose of limiting parental rights is to secure children from being harmed, yet it will infringe children's right to grow up in the family. Owing to children's right to grow up in the family is part of personal rights, which is guaranteed by the Constitution, state should ensure its constitutionality in limiting children's right to grow up in the family. This article believes that the constitutional legitimacy of state to limit children's right to grow up in the family is based on the best interests of the children. Last but not least, family has it irreplaceable functions. The goal of States to limit parental rights is not to replace the functions of family, but to assist family instead.