before three months l started my orthodontic treatment in india(chennai) and the treatment is going on but as iam going to US for my higher studies l cant continue my treatment here and dentist told that it will take maximum 1yr to complete the treatment. if l can how does it will cost in US.

You can absolutely continue treatment here in the United States. As your English is very good, l would suggest that you call around to Orthodontists in your planned area now, as these doctor is usually fill their schedules fairly quickly!
Good Luck and Hope this helps!

l think you really need to continue your orthodontic treatment.
Because if you don't, how will you be fine?

Yes, u will be able to continue ur treatment in the US.

If u can, do the following :

1. It is always better to get a copy of ur dental records.

2. If ur dentist told u that it would take only one year to complete ur treatment, it will help to have those records to see how much malocclusion u started off with.

3. It will be wise for u to get in touch with an Orthodontist ASAP.
You do not want to prolong the treatment by not getting the wires adjusted for long.

4. Maintaining good oral hygiene is a must to prevent decaying.

5. Also, u mentioned that u r coming to US for higher studies.
Try to find out if ur institution has a dental school. In that case u can continue ur treatment at a student discount.

6. Otherwise, u can get a list of Orthodontists from the Yellow Book or go to Yellowbook.com & get a list. You can call them up & find out the price.

7. You can also ask the students who have had the treatment done. Sometimes getting referred by someone helps.

Hope this helps :)

Good luck with ur studies !!

EDIT :

It is very hard to quote a price, because :

1. It can cost upto a few thousand dollars. A likely range will be $2000 - $4000, but do not quote me on this. It can be higher or less.

2. It varies with the case. Depends on how involved it is.

3. Every practice charges different fees