The advanced fighter aircraft's onboard electronic equipment is developing towards high power, high integration, and miniaturization, which results in a continuous increase in heat generation and heat flux and poses a serious challenge to airborne thermal management. With a transport distance of 2.30 meters and ammonia as the working fluid, a high-power dual compensation chamber loop heat pipe（LHP） was created in response to the aforementioned specifications. A comprehensive and systematic experimental study on the dual compensation chamber loop heat pipe was conducted, mainly focusing on its startup characteristics, heat transfer capacity, and thermal resistance change. With a heat transfer capacity of over 900 W, the testing findings demonstrate that the dual compensation chamber loop heat pipe can successfully accomplish startup and run smoothly under a variety of evaporator attitudes, including horizontal, favorable, and unfavorable attitudes. The system thermal resistance of the dual compensation chamber loop heat pipe first rapidly decreases and then gradually increases with the increase of the heat load, and the minimum value is about 0.063 ℃/W. This work provides a new technological means and a feasible solution for efficient thermal management of future airborne systems.