[Objective] To analyze the characteristics and causes of flood disasters in Hanyuan County, Sichuan Province in Qing Dynasty, in order to provide scientific support for disaster preventions and mitigations. [Methods] The flood disaster data of Hanyuan County in Qing Dynasty was collected. Mathematical statistics analysis methods were used to study the level, frequency, period and causes of the flood disasters in Qing Dynasty. [Results] There were 55 flood disasters with an average frequency of once per 4.87 years in Hanyuan County in the Qing Dynasty. Mild floods, moderate floods, major floods and catastrophic floods accounted for 14.55%, 60.00%, 21.82% and 3.64% of the total flood disasters, respectively, with moderate floods being the main events. Flood disasters showed a fluctuated increasing trend and obvious stages. The periods during 1644-1739 and 1770-1809 were the stage of frequent flood disasters, the periods during 1740-1769 and 1810-1911 were the stage of high-risk flood disasters, and there were five major flood events. The flood disasters in Hanyuan County in Qing Dynasty were marked by a shock period of about 5 years and 10 years, and the flood frequency was high. [Conclusion] There is a high probability of flood disasters in the extreme years of the sunspot, the prosperity period of India summer monsoon and the year of the ENSO events. The rapid of population growth, agricultural reclamation, forest destruction and human-made disorderly development aggravated the frequency and severity of flood disasters.