In real life, it is not uncommon for one party to borrow another's identity document to register marriage because it has not reached the legal age for marriage. If the subject stated on the marriage certificate objects to the validity of the marriage certificate, it can request the civil affairs department to cancel the marriage registration or directly file an administrative lawsuit; If the party who actually lives together applies for divorce, the court shall clarify the party and inform him that due to the flaws in his marriage registration, the two parties who apply for divorce do not match the subject specified in the marriage certificate, and it is impossible to judge whether the two parties have a marriage relationship. If the parties insist on their claims, they shall rule to dismiss the lawsuit; If the parties change their claims and claim to solve the problems of property division and child rearing during cohabitation after the court explains, the court can continue the trial according to law. It is worth noting that if the parties lived together in the name of husband and wife before February 1, 1994, they can be treated as de facto marriage. The validity of marriage certificate is the result of specific administrative action. The target is specific, which is only binding on the subject specified in the marriage certificate, and should not extend to others. In China, there is only one form of marital relationship establishment, that is, the registration mode is adopted. Only the applicants recorded in the marriage certificate are the parties who are allowed by the administrative organ to enter into marriage and recognize the marital relationship. When an administrative organ issues a marriage certificate, what it actually establishes is a valid legal document of the husband and wife relationship between the person whose identity certificate is borrowed and the person who holds the real identity certificate. It has the effect of publicity and public trust. It is a legal marriage relationship in form, and its effect cannot be directly denied until it is revoked by the legal organ through legal procedures. Based on the relativity of administrative acts, the validity of the marriage certificate should not extend to the parties who actually live together, and there is no legally recognized marriage relationship between the parties.
 3、 How to identify fraudulent marriage is actually one of the crimes of fraud, that is, the act of cheating the other party of a certain amount of property in the name of marriage. In practice, to judge whether it is fraudulent marriage, we should first see whether the two parties are married, and then see whether the other party cheated a certain amount of property. It can be identified from the following aspects:
 1. In terms of time, the subjective intention of obtaining money by marriage occurred before marriage.
 2. In terms of behavior, he used the method of fabricating facts and concealing the truth to cheat the victims' trust. After obtaining property by deception, the perpetrator will use the property for personal consumption.
 3. As for the ownership of the money defrauded, the property defrauded is the premarital property of one party or the property of other people related to the victim, not the common property of both "husband and wife" after the establishment of the marriage relationship. In case of fraudulent marriage, you can claim to return the betrothal gifts. Interpretation of the Supreme People's Court on Several Issues Concerning the Application of the Marriage Law of the People's Republic of China
 （2） Article 10 stipulates that the people's court shall support a party's request for the return of the betrothal gifts paid according to custom if it is found that the following circumstances exist:
 （1） Both parties have not gone through marriage registration procedures;
 （2） Both parties have gone through the marriage registration procedures but do not live together;
 （3） Giving money before marriage and causing difficulties for the payer. The preceding paragraph applies
 （2） 
 （3） The provisions of subparagraph (1) shall be conditional on the divorce of both parties.