Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -name "PortNumber"

$portvalue = 3390

Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -name "PortNumber" -Value $portvalue 

New-NetFirewallRule -DisplayName 'RDPPORTLatest-TCP-In' -Profile 'Public' -Direction Inbound -Action Allow -Protocol TCP -LocalPort $portvalue 
New-NetFirewallRule -DisplayName 'RDPPORTLatest-UDP-In' -Profile 'Public' -Direction Inbound -Action Allow -Protocol UDP -LocalPort $portvalue 

Reference

• 更改计算机上的远程桌面的侦听端口