In response to the requirement that the aircraft inertial navigation system needs to obtain the heading angle through initial alignment before launch, an indirect initial alignment method based on structure transfer is proposed; the initial alignment process is decomposed into the final assembly alignment and launch alignment. The transfer and measurement of the aircraft’s inertial navigation system heading angle are realized by the base surface conversion device and the aircraft surface-mounted prism; theoretical error analysis and ground tests show that the method could meet the initial alignment accuracy requirements of the general technical verification demonstration aircraft. The method successfully avoids the aircraft design additional initial alignment windows,simplifies the aircraft launch site requirements and effectively shortens the aircraft’s preparation time before launch.