Based on multivariate random analysis and statistical physics, the reliability model of a system with stress-strength interference and initial failure is developed, the system has multi-state and dependent multi-subsystem. According to the definition of conditionally ordered order statistics, the probability density function of random strength vector is studied. Considering the coherence of subsystem items, the system reliability evaluation for different structures is given, and the reliability of any coherent structure is represented as a linear combination of the reliabilities of (n－i+1)-out-of-n system(1≤i≤n). Finally, an example is given to demonstrate the effectiveness of the model, where the stress-strength variable has a bivariate Pareto distribution.