The "Family Break-up Law" in the Song dynasty changed a lot with the modification from emperors of Song Zhenzong, Song Renzong, Song Xiaozong to Song Guangzong, in that the property right of children in a family was gradually recognized by the Court. The items of "Family Break-up Law" were issued in a special law from Song Taizu to the early years of Song Renzong; the property earned by the children themselves was recognized by the Court in the 4th year of Jingyou and became legal even when their parents and grandparents were still alive in the years of Song Xiaozong; the law was modified slightly in the time of Song Guangzong. Two important factors that contribute to the change are the heavy burden on people from the office service corvee and numerous property law suits during that time. In fact the implementation of this law is not as ideal as supposed