我试图把标题，但它完全

$news = htmlspecialchars(file_get_contents("https://www.ethnews.com/rss.xml"), ENT_QUOTES);

echo $news->channel->item[0]->title;

You may want to use simplexml_load_file(), i.e.:

$url = "https://www.ethnews.com/rss.xml";
$feed = simplexml_load_file($url);

foreach($feed->channel->item as $story) {
    echo $story->title;
    # other options :
    # echo $story->desc;
    # echo $story->link;
    # echo $story->date;
}

If you just need the first title, you can use:

$url = "https://www.ethnews.com/rss.xml";
$feed = simplexml_load_file($url);
echo $feed->channel->item[0]->title;