The succession order of the legal heir is mainly determined according to the blood relationship between the heir and the decedent, the closeness of the marital relationship, and the legal obligation of mutual support. China's Inheritance Law stipulates that spouse, children and parents are the first order heirs; Brothers and sisters, grandparents and maternal grandparents are the second order heirs. After the beginning of succession, the successor in the first order shall inherit. If there is no successor in the first order or if all the heirs in the first order give up their right of inheritance or lose their right of inheritance, the successor in the second order shall inherit. Among the heirs in the same order, there is no order of succession. Generally, the inheritance is divided equally. In addition, widowed daughter-in-law and father-in-law, widowed son-in-law and parents in law have no blood relationship, nor the right to inherit inheritance from each other. However, many widowed daughter-in-law and son-in-law have done their duty to support their parents in law and father-in-law in life, which is very valuable. Therefore, Article 12 of the Inheritance Law also stipulates that: "If a widowed daughter-in-law has made major contributions to her mother-in-law and a widowed son-in-law has made major contributions to her parents in law, they shall be the first in line heirs." It can be seen from this that whether a widowed daughter-in-law or a widowed son-in-law has made full contributions to their parents in law is a prerequisite for inheriting the estate of her mother-in-law or parents in law. As long as they meet this condition, they will not be affected by whether they remarry or not, and their inheritance will not affect their children's right of subrogation. The scope of heirs includes: spouse, children, parents and siblings, grandparents, maternal grandparents. As legal heirs, children's inheritance rights are not restricted by sex, age, legitimate and illegitimate (see illegitimate children). An adopted child has the same right of inheritance as a natural child. However, because "the rights and obligations between the adopted children and their biological parents are eliminated due to the establishment of the adoptive relationship" (Article 20 of the Marriage Law), the adopted children lose the right to inherit the inheritance of their biological parents (see Adoption). According to the relevant provisions of the Marriage Law, the right of inheritance between stepchildren and stepparents shall be limited to those who support each other. The right of mutual inheritance between a widowed daughter-in-law and her in law, or between a widowed son-in-law and her parents in law, is also determined in judicial practice by their support relationship. For children born after the death of their father, that is, posthumous children, inheritance laws of all countries in the world specifically stipulate to retain their share of inheritance. If the fetus survives after birth, the inheritance will be obtained; In case of a dead baby, the share reserved for him shall be distributed by other legal heirs. Brothers and sisters are the nearest collateral relatives. Not only brothers and sisters of the same parents, but also half blood brothers and sisters of half parents or half parents have the right to inherit from each other. Grandparents and maternal grandparents have the same right of inheritance.