"diandongosuchus" is known from a nearly complete articulated skeleton (zmnh m8770) missing most of the tail. the total length of zmnh m8770 is and the estimated body length of the animal in life is around . the specimen is preserved on its right side, with the underside of the lower jaws and the trunk showing. it was prepared out of a limestone slab to reveal details on the left side of the skeleton, many of which are better preserved. the skull of "diandongosuchus" is pointed, with oval-shaped eye sockets, antorbital and temporal openings. distinctive features include a long premaxilla bone at the tip of the snout that extends backward past the nostril openings, a large ridge on the jugal bone that runs beneath the eye socket, and two supratemporal openings on the skull table that have prominent ridges surrounding them. the skull has similar proportions to that of "qianosuchus", and has the same number of teeth in the premaxilla. like the terrestrial poposauroid "poposaurus", "diandongosuchus" has a maxilla (upper jaw) bone that does not reach the border of the nostril opening.