Objective: To examine the prerequisites of sleep problems among a traumatized population, and assess the underlying mechanisms of sleep problems following trauma. Method: The current study investigated 187 flood victims from 5 makeshift shelters in the Wuhu city of Anhui province after a major flood disaster that occurred in July 2016. A traumatic exposure questionnaire, a fear questionnaire, a posttraumatic cognition inventory, a depression inventory, and a sleep problems questionnaire were used. Results: Traumatic exposure had a direct and positive association with sleep problems and could also be indirectly associated with sleep problems through fear, depression, but not negative cognitions. The positive association could be the result of a path from negative cognitions to depression, but not from fear to negative cognition, or from fear to depression. Furthermore, a threefold multipath from fear to depression via negative cognitions could also link traumatic exposure to sleep problems. Conclusions: Flood victims’ sleep problems are elicited by the combined role of fear, negative cognitions, and depression following trauma.