The project design of commercial aircraft, together with the project management need to solve the conflicts among technological advancement, R&D cost and operating economics. Therefore, a scientific and systematic methodology of technology economics is in great needs for accomplishing goals of the project by guiding and regulating the decision making process during aircraft design. This methodology contains LCC model, pricing model and optimization mode, which consider market factor, technology factor and economic factor. This essay through three examples illustrates the use of technology economics method in commercial aircraft.