In order to further expand the application scenario of large and medium fixed-wing UAVs under harsh conditions, this paper summarizes the development process of rocket-propelled takeoff of UAVs at home and abroad and designs two methods of propelled takeoff based on MQ-9 public data. The takeoff control logic is decomposed in detail, and the takeoff control logic is divided into three flight phases. The advantages and disadvantages of rocket boost and no rocket boost are simply analyzed by software simulation, which has a certain reference value for rocket boost takeoff mode analysis of large and medium fixed-wing UAVs. Based on literature research and qualitative analysis, this paper summarizes the key points of the rocket boosting takeoff process, such as rocket consistency, installation symmetry, center of gravity change, takeoff process, etc. This study provides a reference for the design of the rocket-boosted takeoff scheme of large and medium-sized fixed-wing UAVs and solves the takeoff conditions of plateau takeoff and insufficient runway.