By analyzing the characteristics of electric vehiclescharging behavior，a queuing model for charging facilitiesservice system for electric vehicles based on queuing theory is established.On this basis，the waiting probability characteristics of charging facilitiesservice system for electric vehicles are studied，and the operation efficiency of charging facilities for electric vehicles is analyzed quantitatively.Furthermore，an optimal cost model for electric vehicle charging facilities is developed with the minimum of the total cost of service system as the objective function.By referring to the forecast results of electric vehiclespower demand，the influence of different charging facilitiesallocation schemes on load factors of power grid is analyzed.The analysis results show that the synthetic efficiency for charging facilities utilization can be improved by reasonable allocating charging facilities，and the practicality and effectiveness of the model are further verified.