	"Diandongosuchus" was found in a Ladinian-age marine limestone formation that has preserved many marine reptiles including thallatosaurs, nothosaurs, pistosaurs, and some protorosaurs. The closely related pseudosuchian "Qianosuchus" was found in a marine deposit about northwest of the "Diandongosuchus" locality that is slightly older (Anisian in age) and possesses many features consistent with a marine lifestyle. However, "Diandongosuchus" shows no features that are clear adaptations to a marine lifestyle. Possible adaptations include nostrils that are positioned slightly farther back on the skull than most terrestrial pseudosuchians and a greater number of premaxillary teeth (a feature seen in possible semiaquatic archosaurs such as "Chanaresuchus" and spinosaurids). Fish bones within its stomach contents are additional evidence that it was a marine archosaur. "Diandongosuchus" may have had a similar lifestyle to modern marine crocodylians like the saltwater crocodile that live along coastlines yet are not fully marine.