Spares support is one of the most important aspects of the airlines cost control. A reasonable level of spares support could lower the procurement cost, reduce the inventories, and improve the comprehensive competitiveness of airlines. According to the practical engineering application, we introduced the significance of spares support engineering, and emphatically discussed the general developing method of the RSPL(Recommended Spare Parts List) during the initial service based on the specific requirements for the new type of aircraft. The validity and practicability of the method presented are verified by a example, which could be used to guide the initial spares support of the airlines.