i brough the car under my name for my sister a years ago (she have
very bad credit) she made payments and pay for the insurance,I want to know that
any way legaly that to make her responsible if any things  happens to
the car.Like do a  agreement in written some think like that.

What state are you in?
This is no legal advice (see the disclaimer below), but I would
suggest a contract allowing her sole use of the car (maybe a lease
contract) and requiring her to provide the necessary insurance, under
the condition that she provide you with confirmation of the insurance.
 Maybe you as owner must have the insurance, then the contract should
make her responsible for reimbursing you for the premium payments and
any eventual costs if there is an accident or theft.
This would be safer for you, if necessary, but an accident would
probably go against your insurance record.

Title the car in her name.  As long as your name is on the title, you
can be looped into responsibility with her.

you cant... as long as you own the car you can be listed on any
lawsuit( or action)...the prev commet said to tile/register the car in
her name (then she would own the car but the current leinholder would
not let you) ....you could sign the car over to her and list yourself
as a lienholder if the car is paid off (you could look at getting a
signature loan to pay off the current loan) then have her pay that
loan

I don't know why I didn't think of this sooner.  It's very simple. 
Draw up a lease contract between you and your sister.  Legally, you
will lease the car to her by contract.  In the contract, of course,
you will have her indemnify you for any responsibilities or
liabilities arising out of the car.

Perfecto.