Constantly Risking Absurdity
The speaker tells us that the poet is like an acrobat, always risking both absurdity and death as he flails around above the audience of his circus. And that high wire he's on? Well, he made it himself. So the gist here is that our speaker thinks poetry is pretty much the same thing as a circus act. At least, in some ways.
And what's this circus act all for? The pursuit of Beauty, which he may or may not nab in all his twirling and leaping. Sounds like poetry's a bit of a crapshoot.