Abstract: Dammed lakes are characterized by suddenness,high impact and wide range of influence, which seriously threaten the lives and properties of people downstream. Rapid assessment of the potential loss of life is of great significance for emergency decision-making, emergency evacuation and other emergency response activities. In order to achieve timely, rapid and accurate assessment, this paper constructs a system of rapid assessment methods for barrier lake breaching loss of life based on simplified parameters, analyzing and calculating four modules respectively, barrier body stability, outburst flood peak, failure flood evolution and loss of life, and validating them using the Baige Dammed Lakes event with an accuracy rate of 65%. On this basis, the Shiping landslide, which has a high risk of river blockage in the Minjiang River Basin, was selected for prediction and analysis. The stability of the barrier body was assessed through the methodological system proposed in this paper, the peak flood flow under full breach conditions and its flood evolution were calculated, the impact range caused by the flood risk on the Wenchuan County town of Weizhou was delineated, and the possible missing or dead population caused by the flood was predicted. The results of the case calculations show that under partial alarm conditions, the Shiping landslide barrier lake breaching will result in a loss of population of approximately 753 people in Weizhou town, and that disaster prevention, mitigation and preparedness work such as monitoring and early warning, emergency planning and emergency evacuation drills need to be strengthened to reduce disaster risk. A basis for disaster prevention and mitigation planning and emergency response and decision-making for Dammed Lakes can be provided through the establishment of this rapid assessment method system for loss of life.