Yesterday I registered pool.com, it needs me to fill my credit card number, and I did as requested, but once i
registered successfully, a message remind me $60 has been deducted from my credit card. I want to know
what's going on, and how can I get the money back? Does somebody knows? Thank you!

I have got the answer.

The transaction i was said is only a credit card pre authorization.
A pre authorization is only a temporary request to reserve $60 USD, to help pool to verify the credit card is valid. The pre authorization will eventually be removed by our credit card bank and typically this happens within 2-3 business days from when the pre authorization was added, but some credit card banks may require more time.

One you paid and getting back is not possible i think. Check it exactly i too dont know much