This paper applies Monte-Carlo sampling method in reliability evaluation of composite power system. Performance of system is studied in both static and dynamic aspects on the basis of detailed modeling of state of all the elements. The main work includes element state sampling, network topology analysis, load flow calculation, step-by-step (SBS) transient simulation, real power generation re-dispatching, reactive power and voltage correction, and introduction of various emergency control measures (ECMs) and security and economic strategy. It constructs integrated framework and risk index system of composite power system evaluation.