Those who hold green cards are legal immigrants, and the three powers in the United States are separated. Trump is only the president, but the court has the highest power. Unless Trump amends the law and Congress passes it, there is a chance to expel immigrants with green cards, and they will get green cards later (because laws are generally retroactive after legislation, not before legislation).
Therefore, China people will not be driven away. In fact, according to TV reports, there are not a few people in China who choose Trump. . .