Im gone open a new character but i dont want to mess with main questline.How do i finish them?Will oblivion gates close after finishing main questline?(i dont want them to close :/)

Sorry for bad English.

I have lots of characters that don't do the main questline.

I just don't deliver the amulet after leaving the sewers.

Ok than.There was a cheat code that finishes main questline,but that codes finishes all side quests too?

Why bother with a console command, when you can just not deliver the Amulet?

I finish the main quest line cause I hate the oblivion gates

There seems to be some contradictions within your question, so let me just share some options that may be of interest:

If you just keep the amulet or drop it off with Jauffre and move on, only the Kvatch gate will be open and you have a stable Cyrodiil. You said you don't want to mess with main questline.

If you close the Kvatch gate and ignore Martin (leave him in Kvatch), zero gates will be open and you have a stable Cyrodiil. You said you don't want to mess with main questline.

If you escort Martin to Weynon Priory, up to 25 random gates will open. If you leave Martin there and ignore the gates, you will have a stable Cyrodiil with 25 gates open. This is nice if you like wandering around with some gates decorating the landscape. You said you don't want them to close.

If you complete the Dagon Shrine quest and stop at that point, you will have up to 50 or so gates open as you wander Cyrodiil. This would be if you want a stable Cyrodiil with lots of gates open.

Reference: http://www.uesp.net/wiki/Oblivion:Oblivion_Gates

hmm.. I atleast deliver the amulet just to get the damn thing out of my inventory.

the gates will only appear once you close the one at kvatch.

Actually the gates will only appear once you have escorted Martin to Weynon Priory. I take every character I make to the point of closing the Gate in Kvatch. Then I leave Martin in the camp and go about my business. I don't have the amulet in my inventory, I am still greeted as the Hero of Kvatch, and no further Oblivion Gates open. I have been playing the game for 3 years with many characters and I have never once completed the main quest.

Thank you for your advices.The console commands in UESP helped me much.