The analysis of cost-effectiveness is a measure of spare parts system utilization ability, and a function of costs in life circle. It aims to provide policy makers with the information of efficiency and cost ratio, the basic task is to search for the best proposal according to the relationship between the target value and the resources consumed. However, spare parts life circle cost is sensitive to various factors and has the traits of obvious uncertainty, so the comprehensive assessment of the cost-effectiveness becomes more complex. In this paper, Cost-effectiveness of spare pares has been analyzed, and a type of solution to the comprehensive assessment on spare parts life circle cost-effectiveness in which the gray analysis method has been applied. On this basis, the corresponding weights according to relative importance of the primary factor of efficiency function on spare parts life circle cost has been determined. Finally, the assessment method and its practical example analyzed.