My girlfriend, she now asks me to wake her up every day to exercise, but I'm not very humorous. What should I say to make her get up early is also humorous.

This may be difficult. If you really don't understand humor, even if it is funny and cute, it will be strange to say it from your mouth. So, I can't help you. You can find some funny jokes to make her get up with a smile as soon as she picks up her cell phone in the morning, so that she will think you are romantic, and then you can find a very suitable time (basically, you have a happy day and then have a nice meal, and chat while drinking tea or wine) to tell her what you did and what you thought, and I promise she will be moved.