How can I sue for alimony if I immigrate but still stay in China?

Go directly to the local court of the other party's residence (or habitual residence) to file a lawsuit as a foreigner.

According to Article 5 of the Civil Procedure Law of People's Republic of China (PRC), foreigners, stateless persons, foreign enterprises and organizations have the same litigation rights and obligations as citizens, legal persons and other organizations in People's Republic of China (PRC) when they sue and respond to lawsuits in the people's courts.

Therefore, the court must accept it.

If the object of prosecution is in the United States, then it is necessary to return to the American court for prosecution.

The parties have the responsibility to provide evidence for their claims:

(a) Statements of the parties;

(2) Documentary evidence;

(3) Physical evidence;

(4) Audio-visual materials;

(5) Electronic data;

(6) Testimony of witnesses;

(7) Appraisal opinions;

(8) Records of the inquest.

Original household registration book, paternity test, birth certificate and so on.