What does it mean when I run this line of code?

When I run:"~/.local/bin/jupyter notebook",
I just got this result: [C 03:19:35.006 NotebookApp] \u4e0d\u5efa\u8bae\u4ee5root\u8eab\u4efd\u8fd0\u884c.\u4f7f\u7528–allow-root\u7ed5\u8fc7\u8fc7.

What does it mean? Why I can not run the jupyter notebook

Something’s wrong with localization or the logging configuration, because it should be showing you the text, not unicode code points. If you print that string, it should make more sense:

In [2]: print('\u4e0d\u5efa\u8bae\u4ee5root\u8eab\u4efd\u8fd0\u884c.\u4f7f\u7528–allow-root\u7ed5\u8fc7\u8fc7')

which I can’t read, but I know what the message should mean: Jupyter refuses to run as root by default unless you pass an explicit --allow-root argument. You must either run as a non-root user or add the --allow-root flag to confirm that running Jupyter as root is really what you intend to do.