The new rules would make migrants ineligible for asylum unless they sought asylum in the first "safe" country they passed to.
The Supreme Court on Wednesday approved President Trump's request to allow the administration to enforce its new asylum rule even as it is challenged in the courts.
The decision was issued in an order. Justices Sonia Sotomayor and Ruth Bader Ginsburg, two of the court's four liberal justices, dissented.
The order is a victory for Trump, who has vowed to take action to stem the tide of immigrants at the southern border, most of whom are coming from Honduras, Guatemala and El Salvador.
The new asylum rules are expected to severely cut down on the number of immigrants from Central America who can request asylum in the United States, essentially preventing many of those coming from that region to do so.