Is there a conflict between American green card and China nationality?

there is no conflict.

A green card is actually a kind of identification of a non-American citizen who has lived in the United States for a long time. It has nothing to do with nationality. If you become an American citizen, it is just like changing your birth address in your household registration book, so you are an American citizen, and you can't have China citizenship.

as long as you don't have the nationality of another country, you are always a citizen of our country.

according to American citizenship and immigration law, green card holders are foreigners who have neither American citizenship nor American citizenship. However, it basically enjoys the same treatment as its own nationals in the United States, but it has no right to vote and stand for election.

according to the immigration law of the United States, permanent residents must use a valid immigration visa and a valid passport of their home country when entering the United States, otherwise they are not allowed to enter the country. After having an American green card, as long as you leave the United States for less than one year, the green card itself can be regarded as a valid entry immigrant visa, and you don't need to apply for another visa at the American embassy or consulate.

if you leave the United States for more than one year, you must apply for a re-entry visa before leaving the country. As a valid immigrant visa, the re-entry visa is valid for up to two years. Cardholders who have not entered the United States for more than a period of time are likely to be sentenced to lose their permanent residency when they enter the country, because the immigration law requires green card holders to leave the United States only temporarily.

The permanent residency defined by the US immigration law is a privilege granted by the immigration law to live permanently in the United States as an immigrant, and this status has not changed. This means that if the green card owner changes his identity, his right to permanent residence will be extinguished immediately.

Therefore, a permanent resident will be terminated at the same time unless he uses an inconsistent identity unintentionally. In addition, according to the case law of the United States Court of Appeals for the Federal Circuit, permanent resident status can be automatically lost by giving up, without having to fill out the form or pass the judgment of the immigration court first.