Abstract: The mechanism of the tailings dam accident is analyzed on the basis of the typical accident of tailings dam break investigation，including planning，design，construction，flood damage，overtopping seepage and earthquake damage. Secondly，the influence of tailings dam crash on ecology environment is studied，including pollution of water resources system，soil pollution，soil erosion. Then，the countermeasures to prevent tailings dam destruction and to ensure the safe running of tailings dam are raised. The research results have a certain reference value for the safety supervision department and safety management of tailings dam.

Key words: Tailing dam, Mechanism of the dam break, Ecological environment impact, Safety supervision countermeasures