Abstract: Redundant configurations are commonly used in high reliability industrial systems,such as nuclear power plant,aeronautics and aerospace,to improve the reliability of systems.But dependent failures can significantly reduce the benefits of the redundancy.The failure mechanism is analyzed to interpret that dependency is a common characteristic of system failure and dependant failure can have significant impacts on system reliability and safety in the present paper.A more practical stress-strength dynamic interference model is created to simulate the failures of systems using Monte Carlo method.The major factors influencing dependent failure are analysed.A few measures are introduced to reduce dependant failure probability.