When you have to fight with Durnehviir later you take the scroll and when you get out of there you see Durnehviir and he speaks with you.My problem is that when I saw him for second time I thought that he wanted to kill me and I attacked him.Now I finished Dawnguard and I don't have his two shouts.What can I do to find him again.

You summon him using a shout, he only teaches you one word in the soul cairn. The other two are learned when you summon him into Skyrim. If when you summon him he is hostile the only solution I think would be to reload an earlier save.

I haven't any earlier save

Always make backup saves, they are life savers

Sorry I edited my post. To answer it better. Also you should have more than one save in the middle of a quest. Only delete them after it is done and you are sure there are no errors.

I don't have the shout to summon him because I attacked him the second time because I thought that it was one more fight

Crap! I attacked him too...and saved over the top of everything I had from the Soul Cairn. Oh well, the only shouts I really use are Dragonrend and Unrelenting Force.

I don't use it but I want those shouts

Well then, too bad. Sorry but if you don't have an earlier save then there is no way that you can get it. Unless you go back to the Soul Cairn and re talk to him again. Try that, it probably won't work but it's worth a shot, right?