<p>Currently, civil unmanned aerial vehicles (UAVs) are developing toward being heavier and more maneuverable, leading to a geometric growth in the energy required for ejection, which poses huge challenges to traditional ejection methods. The sixfold pulley range-extending ejector system can convert the cylinder stroke into sixfold rope displacement, greatly improving the launch efficiency and effectively addressing this issue. This study proposes a pulley range-extending internal ballistics calculation method based on rigid equivalent load, verifies it through experiments, and discusses the influence of the reaction of the load system. The main innovations are as follows: (i) realizing effective ejection of large-mass loads through a sixfold pulley block; (ii) establishing a rigid equivalent load model that considers factors, such as friction and pulley rotation, providing input for rigid internal ballistics; and (iii) compared with the traditional finite element simulation method, this method significantly improves computational efficiency and is suitable for rapid iterative optimization in engineering design. This system can be applied to the takeoff and landing of logistics UAVs in mountainous areas without runway conditions, as well as the airdrop system of heavy equipment in emergency rescue scenarios. The ejector scheme with a sixfold range-extending pulley block proposed in this paper provides a reference for the current high-speed and heavy-load ejection.</p>