The purpose of the paper is to improve the method available for estimating the procurement cost of turbofan engines for large civil aircraft. A new approach to analyze the R&D cost and production cost is studied based on the domestic and foreign studies. The newly developed turbofans are used to evaluate the accuracy of the method. Engine list price is the reference to the market price. Procurement price is mainly determined by the market competition situation. Procurement price could be at big discount based on the negotiation between the engine manufacturers and the customers. Launching customers, big leasing companies and big airlines (groups) tend to have big discount. Pricing practice of Rolls-Royce's aero engines is studied as an example of buying big civil turbofan engines. The results show that the estimation methodology of procurement cost is rational; the calculation is simple and practical; the precision of the calculations is accepted for the real requirements.