The Dragons were searching for their first victory at the Stadio di Monigo but the game got off to the worst possible start as Alessandro Zanni touched down followed by a brace from Brendan Williams inside the opening 15 minutes.
Jason Tovey came off the bench to kick a penalty for the Dragons just before the break but Kris Burton cancelled it out with one of his own to add to his three previous conversions for the hosts.
South African Tonderai Chavhanga gave the Dragons hope with a try just after the break but Treviso then showed their dominance scoring 26 answered points with tries from Ludovico Nitoglia, Tobias Botes, Robert Barbieri and Paul Derbyshire. Chavhanga and Steffan Jones grabbed tries late on for the visitors but it was too little too late.