Two different Apple IDs with two different @icloud.com mails I have a complicated problem. It started when I created an apple id with icloud email. Later after some months, I created anther apple id with a new icloud mail. Now, I am using this new apple id on my apple devices. 

My Problem:
I need to use my old icloud email on my new apple id. In other words, I want to terminate my current (new) icloud mail and move the old icloud mail so I can use it with the new apple id instead.

I tried different ways, but no solution! Is it possible ?
No - if you really have two different AppleID each with different @icloud/@me/@mac addressed - they cannot be merged or swapped one for the other. If you just want to use the @icloud.com to log in to one AppleID that's also known by a different email address - you can do that easily by changing the username on each device.

See Apple ID - Want to make my xxx@icloud.com primary Apple ID?

If you have two AppleID - the best you can to towards merging them might be to make a family plan and share purchases and migrate mail/contact/calendar data off the account you wish to avoid.

See Renaming iCloud mail address for that.