[問題] 請問如何用 beamer 製作一頁四張

I think xelatex causes the problem. pdflatex should give you the right layout you want.

If you have Chineses involved, then change to CJK environments.

PS: Handout is the right way to go, making your class note attractive and professional as well.
→ haharq:有試過 pdflatex 編譯，不論是否有用 CJK 環境，問題都一樣