legal ground
Article 1085 of the Civil Code of People's Republic of China (PRC)
After divorce, if the children are directly raised by one party, the other party shall bear part or all of the support. The amount and duration of the expenses shall be agreed upon by both parties; If the agreement fails, the people's court shall make a judgment.
The agreement or judgment stipulated in the preceding paragraph shall not prevent the children from making reasonable demands to either parent over the original agreement or judgment when necessary.
Article 42 of the Supreme People's Court's Interpretation on the Application of Compilation of Marriage and Family (I)
The "alimony" mentioned in Article 1067 of the Civil Code includes children's living expenses, education expenses and medical expenses.