Abstract：Based on the theory of muti-rigidbody kinematics，from a viewpoint of work-energy transform principle and momentum theorem as the entrety，the stability of slope under the impetus actions of rockfall is analyzed；and the critical threshold conditions(the mass center descent obliquity and effective descent distance) of collapsesand landslide disaster chain are studied. The theory for collapses and landslide disaster chain is extablished. Based on the results of Liziba—Hulongqiao slope in Chongqing，the accuracy of this theory is validated and the results show that this theory could better reflect the actual situations of collapses and landslide disaster chain，with considerable precision. The results can provide reference to the study of associated mechanism on collapses and landslide disaster chain.
