New fixture has 3 wires 1 bl. 1 white and a ground, coming from ceiling I have 3 wires 1black hot, 2 white one is hot. How do I wire this?

Sounds like a switch loop. How was the old light connected? Pull the wall switch, tell us the colors and get back to us. Typically, the ceiling hot black goes to a white, down to the switch, the black at the switch comes back up to the ceiling and goes to the fixture black. Ceiling white goes to fixture white. Hot white should have black tape on it. Google "switch loop" for details.
Here is an example.http://www.wurtsboroelectric.com/sitebuildercontent/sitebuilderpictures/swloop.jpg