Abstract: Landslide-debris-flow disaster chains are characterized by abrupt initiation, severe consequences, and complex formation mechanisms. In the distinctive terraced landforms of Yunnan, such disasters are strongly influenced by topography and human activities, and their triggering mechanisms and movement processes show clear regional and dynamic characteristics. With the increasing frequency of extreme rainfall, landslide-debris-flow geohazards have repeatedly occurred in the cultural landscape of the Honghe Hani Rice Terraces, causing extensive damage to terraces and vegetation along their paths. Taking the Laohuzui terraced-field landslide-debris-flow event as a case, this study uses field investigation, geotechnical laboratory testing, and Massflow numerical simulation to analyze its development characteristics, disaster-forming pattern, and chain-generation mechanism. The results show that the Laohuzui event exhibits a clear chain-type disaster-forming pattern that can be summarized as a three-stage evolution process: upstream landslide initiation, midstream terrace erosion and transformation, and downstream deposition and burial. Coupled instability of the new and old landslides was the initiating link of the disaster chain. Movement of the new landslide reactivated the old landslide, producing cascading instability and supplying approximately 31.3×10⁴ m³ of source material for the debris flow. Sustained heavy rainfall was the main triggering factor, driving the disaster evolution through infiltration-induced softening and scouring erosion. The terraced landform played a key amplifying role in the disaster chain through water supply, material supply, and lateral spreading. The unique layered-interface-basement geological structure of the terrace farming area controlled the development of the disaster chain; the contact between the cultivated soil layer and the residual-slope deposit may form a preferential seepage pathway and a shear-weakening zone. Numerical simulations show that the debris flow spread laterally when passing through the terraces, with velocities of 2-4 m/s, and the simulation accuracy reached 87.4%. Compared with typical landslide-debris-flow disasters, the disaster chain in this area had a wider burial range and received continuous material and water supply during the transport stage. These findings provide a scientific basis for preventing and controlling similar geohazards in the Honghe Hani Rice Terraces.