"早日当上爷爷" means "to become a grandfather as soon as possible" in Chinese.

This phrase is often used as a way to express a wish for someone to have a child and start a family. It can also be used in a humorous or teasing way to express a desire for someone to get married and start a family.

Here are some examples of how this phrase can be used in Engpsh:

"I can't wait to become a grandfather someday. I hope it happens soon!"
"My friend has been married for a few years now, and he keeps saying he wants to become a grandfather as soon as possible. He's always joking about it."
"My sister is getting married next year, and I'm already looking forward to becoming a grandfather someday. I can't wait to spoil my grandkids!"

In Engpsh, the phrase "to become a grandfather" can be translated as "当上爷爷" in Chinese. The phrase "as soon as possible" can be translated as "早日" in Chinese.