【Purposes】 This research aims to improve the stability of energy system power variation and fuel economy during flight of hydrogen-hybrid fixed-wing UAV. 【Methods】 A variable equivalent factor considering the influence of battery pack power variation amplitude on energy consumption is introduced on the basis of the traditional equivalent consumption minimization strategy theory. This factor is weighted with the original equivalent factor to form a compound equivalent factor. A UAV hybrid simulation platform suitable for complex flight conditions is established, and the influence of compound equivalent factors on the control effect of equivalent consumption minimization strategy is studied. 【Findings】 The results show that the equivalent consumption minimization strategy with compound equivalent factor can effectively reduce the power fluctuation amplitude of the energy system. The amplitude of power fluctuation of hydrogen fuel cell during cruise flight is reduced by 94.7% compared with that of the traditional equivalent consumption minimization strategy, and the accumulative SOC variation of battery pack during flight is reduced by 46%. In 3.5 h flight missions, 193 standard liters of hydrogen can be saved, improving fuel economy. When the SOC of the battery pack approaches equilibrium, the change rate of charging power can be greatly slowed down. The improved equivalent consumption minimization strategy is beneficial to prolonging the service life of energy systems and improving the safety of fuel cells and battery packs.