<p>As the power system of the next-generation fighter jet, the adaptive cycle engine (ACE) has multiple thermal cycle modes, which improves task adaptability. However, its control system also faces technical challenges of multi-mode and multi-variable. This paper proposes an ACE mode decision control method based on matching of the inlet and the engine, which enables ACE to autonomously switch operation modes based on real-time mission flow and thrust demands. First, an integrated model of the ACE propulsion system was established, and the four performance modes of ACE and the impact of variable geometry mechanisms on engine performance were analyzed. Second, the control plan determined the working point of the fan, utilized fan on blade (FLADE) components to manage the overall mass flow rate of ACE, mode selection valve (MSV) and other variable geometry mechanisms to manage the overall thrust of ACE, and completed the performance mode scheduling based on power lever angle (PLA), thereby achieving matching between inlet and engine flow rates while meeting the thrust requirements of different flight missions. Finally, a step simulation from idle to maximum state was conducted at the engine design point. The results showed that the control method achieved a mass flow change of &lt;&#xa0;1%, a thrust change of 51.7%, and a constant installation loss of 5&#xa0;kN during the PLA change from 45° to 115°; for cruise missions, when the instantaneous weight ratio of the aircraft changes, ACE can autonomously change the working mode based on the PLA, thereby making the propulsion system highly adaptable to various flight tasks; and the simulation within the cruise mission envelope proves that this method has good applicability and feasibility in the cruise mission envelope situation.</p>