Annulment of a Marriage on the Ground of Underage
According to the Civil Code, the legal age for marriage is 22 years for men and 20 years for women. If a man or a woman below the legal age for marriage enters into a marriage, a case for revocation of the marriage may be filed by the underage spouse or his/her close relatives.
It should be noted that the case for annulment of a marriage on the ground of underage must be filed before the underage spouse attains to the legal age for marriage. Otherwise, the case will not be admitted or will be dismissed if it has been admitted. And after the underage spouse attains to the legal age for marriage, the right to annulment of the marriage on the ground of underage extinguishes.
The said close relatives who have the right to file an annulment case include the parents, adult children, adult siblings, grandparents, and grandparents-in-law according to the applicable provisions of the Civil Code.
And a case for annulment of a marriage on the ground of underage may not be withdrawn unless the underage spouse is still under the legal age for marriage at the time of admission of the case. And such a case may not be mediated, and the court must make a decree on the validity of the marriage according to law. If such a case involves property division and/or child custody, such issues may be arbitrated.
Robert Zhang 
Steve Li 