Longchuan County, situated in Guangdong Province, was subjected to persistent heavy rainfall from June 10 to 13, 2019. The aggregate precipitation during this interval surpassed 260 mm, resulting in a multitude of landslides and debris flows within the county. Taking the 1 # debris flow in Mibei Village as the research object, based on field investigation and understanding, combined with Fluent numerical analysis, the movement characteristics of small-scale debris flow disasters in such low mountain and hilly areas was investigated. The investigation reveals that the gully connected with the 1# debris flow in Mibei Village displays noteworthy attributes, characterized by a compact length, significant longitudinal gradient, and intricate topographic variations. Variables such as the roughness of the gully bed, longitudinal gradient, and flow direction influence the velocity of the debris flow, giving rise to dynamic fluctuations. Typically, the velocity displays an initial increment followed by a subsequent decrement. Alterations in debris composition also exert an influence on its velocity. Over the entire course, the maximum velocity reaches 9.77 m/s, whereas the mean velocity rests at 3.31 m/s. These values are consistent with findings from empirical investigations. The research results can not only directly provide guidance for the post disaster engineering prevention and control of Mibei Village, but also have reference value for the study of rainfall induced landslides and debris flow disasters in similar areas along the southeast coast.