var
   Isw:TIdStackWindows;
   slist:TStringList;
begin
  Isw:=TIdStackWindows.Create;
  slist:=TStringList.Create;
  try
    Isw.AddLocalAddressesToList(slist);//这个方法可以取出IP
  finally
    FreeAndNil(Isw);
    FreeAndNil(slist);
  end;
end;

var
  sck: TIdStackWindows;
  address: TIdStackLocalAddressList;
begin
  sck := TIdStackWindows.Create;
  address := TIdStackLocalAddressList.Create;
  try
    sck.GetLocalAddressList(address);
    for i := 0 to address.Count - 1 do
    begin
      if address[i].IPVersion in [Id_IPv4] then  //过滤IP_V6
      begin
          Item.Caption := address[i].IPAddress; //item是其他变量
      end;
    end;
  finally
    FreeAndNil(sck);
    FreeAndNil(address);
  end;
end

function GetLocalIP(Multi: Boolean = False): string;
type
  PPInAddr = ^PInAddr; //取本机IP，可取多个(分行列出)
var
  wsaData: TWSAData;
  HostInfo: PHostEnt;
  HostName: array[0..255] of Char;
  Addr: PPInAddr;
begin
  Result := '';
  if WSAStartup($0101, wsaData) <> 0 then
    exit;
  try
    if gethostname(HostName, SizeOf(HostName)) <> 0 then Exit;
    
    HostInfo := gethostbyname(HostName);
    if HostInfo = nil then Exit;
    
    Addr := Pointer(HostInfo^.h_addr_list);
    if (Addr = nil) or (Addr^ = nil) then Exit;
    
    Result := StrPas(inet_ntoa(Addr^^));
    inc(Addr);
    while (Addr^ <> nil) and Multi do begin
      Result := Result + ^M^J+ StrPas(inet_ntoa(Addr^^));
      inc(Addr);
    end;
  finally
    WSACleanup;
  end;
end;