Hello,while confirming that I own the server,I have wrongly click derank the server and lost the rank,is possible to return the rank?

Ranks is not recoverable or assignable.
It must recover naturally

Yes, I naturally got it, click the wrong button and that's it? Now all over again? Not right.

The little help '?' above the button is quite self-explanatory;

"This option allows you to remove your server from the Gametracker.com ranking system. This will reset your server rank to zero. You can re-enable ranking at any time, but it will take about a week for your server to rerank to its previous position.
This feature may be useful if you are not interested in Gametracker.com ranking for you server, and want to limit your servers exposure to attack because of a high rank in the server listings."

The simple solution is: Don't push buttons unless you understand the probable outcome.