I bought a business from a person without lease,ex owner who was not honest with me ,did not shere financial documents , I paid too much and did not show me lease.I thougt I call the lanlord. So, I called the landlord. He said his understanding exowner said you guys just a caretaker, not a owner.so I cannot do any lease with you. Can I ask my money back and get a lawer to win over ex-owner?

... I called the landlord. He said his understanding exowner said you guys just a caretaker, not a owner.so I cannot do any lease with you. ...

That's easy to deal with. If you want to enter into a lease with the landlord, simply show him the agreement by which you purchased the business.

But if you don't think you got your money's worth without a lease, sue the person who sold you the business for recission of the deal.

The choice is up to you.

First it appears you did not ask or demand to do anything. I doubt you have much of a case against the seller.
1. you did not ask to see any books, or refuse to buy without seeing them. Sorry but most courts will just laugh at you for buying without first having an accountant review all of the books closely. He is not at fault for not showing you, you are at fault for buying without looking.
2. Lease, sorry you knew he did not own the building, so you had a obligation to talk to the building owner or manager personally. Why did you not call or go see the building owner before the purchase?

Yes.thats what I like to do-sue the person who I sold the business.but what you mean for recission of the deal?