Source: earthclinic.com pets section
By Robyn Fed from Hampton, TN
Great tip! For smaller staircases, you could also try this:
We once had a rescue boy who came to us also terrified of stairs, and the dog railed against any kind of gentle coaxing; the DH rigged up planks over the stairs to make ramps. Since this dog loved playing ball, we rolled the ball down the planks and he followed soon after. Then we took away one plank and rolled the ball--and he still followed. And then went the other until he didn't care about the stairs any more, because his urge for the ball was higher than his fear level by then.
It only took two days; remember, though, that this was a short, eight foot, stairwell, and we used two four-foot pieces of planking. Any flight of stairs longer than this, or very steep, may not work with this method. Both the OP and our methods really have psychological basis, they are a form of cognitive therapy, not unlike what docs will urge humans to do in order to face fears.
When my sister and I were kids, we had a small poodle named Buttons. He maxed out at 9.5 inches at the shoulder when fully grown. As a puppy, he was afraid to go down the basement stairs. One day, my younger sister had had enough of carrying him up and down the stairs. So she got down on all fours and demonstrated to the puppy exactly how he could go down the stairs, one step at a time. With lots of coaxing and a few more demonstrations, he mastered the stairs, even though he was so short that it looked like he was standing on his head as he made his way down the steps.