The　control　technology　of　the　air　supply　system　is　key　to　the　performance　and　reliability　of　the　fuel　cell　system　(FCS).　However,　due　to　the　low　oxygen　pressure　in　high　altitude　environment,　the　power　consumption　of　the　air　compressor　is　large,　and　the　output　power　of　FCS　is　seriously　degraded.　To　effectively　increase　the　output　power　of　the　FCS　under　changeable　altitude　conditions,　this　article　introduces　a　real-time　power　optimization　strategy　based　on　the　particle　swarm　optimization　(PSO)　feedforward　and　perturbation　and　observation　(P　&　O)　algorithm.　Considering　the　change　of　total　entropy　and　loss　of　centrifugal　air　compressor　with　altitude,　the　working　characteristics　of　centrifugal　compressors　at　different　altitudes　are　studied.　Aiming　at　the　long　optimization　time　of　the　traditional　P　&　O　method　and　the　misjudgment　problem　when　the　external　conditions　change　drastically,　the　PSO　feedforward-based　P　&　O　method　is　designed　to　adjust　the　air　compressor　voltage.　The　results　show　that　the　proposed　strategy　has　real-time　power　optimization　capability　and　can　adapt　to　altitude　change.　The　average　setting　time　is　1.8　s　when　the　operating　condition　changes　and　the　power　decreases　to　9.1%　at　3000　m　altitude　under　a　higher　load　(300　A).