You need to pick an otf font that actually supports Chinese but other than that, it's already working...

from matplotlib.font_manager import FontProperties
from matplotlib import pyplot as plt

plt.title(
    "黑體",
    fontproperties=FontProperties(
        fname="/usr/share/fonts/adobe-source-han-sans-tw/SourceHanSansTW-Regular.otf"))
plt.show()

See #9787 for ttc support and #10249 for font selection issues.

Actually that's essentially documented at https://matplotlib.org/tutorials/text/text_props.html#text-with-non-latin-glyphs. Closing, but feel free to ping with more questions.

@liam-nirvana Glad you got this sorted! Fonts are surprisingly hard....

Same problem. It's really terrible experience to modify the font. Many people fix the problem for hours.....I spent 2 hours on it. Failed.

We can make the experience better by putting #9175 back in with a slightly more verbose error message (it was reverted in #11615 due to other issues).
I'll leave this closed, as #8765 already tracks the same issue.