Is there any solution to see a specific keyword test used in which other keyword tests?

You can find a value but not a keyword, in the Find function. There's no other solution

It's a very useful feature.

I have a keyword test, which used in many other keyword tests.

You mean there is no way to see in which keyword tests, this specific one is used?

Yes, see Find Dialog - "In the Keyword Test editor, the dialog searches for the specified string only within the Value column. You cannot use the dialog to search for operations in keyword tests."