Abstract: The effect of frequency of random loading on the reliability of system is studied, and the reliability models of failure-dependent system under the action of random load are developed by use of the load-strength interference model and theory of order statistics. Considering the failure-dependence on components in the system, the reliability models of series and parallel systems are developed separately by the system-level load-strength interference model without the precondition of failure independence assumed. According to the statistical meaning of random loading, the cumulative distribution function and the probability density function of equivalent load are derived through the order statistic theory when the random load acts many times. Thus, the reliability models of failure-dependent systems are developed when the random load is acting on them many times. The Monte Carlo method is then applied to the simulation experiment for the reliability model of failure-dependent series system on which the random load acts many times and the result shows that the model proposed is effective.