Developing　high-performance　latent　heat　storage　units　is　an　effective　means　of　efficiently　using　solar　energy　and　achieving　energy　savings　and　emission　reductions.　A　two-stage　phase　change　thermal　storage　(PCTS)　unit　model　incorporating　multichannel　flat　tubes　(MCFTs)　and　compact　fins　is　established.　A　numerical　simulation　study　is　conducted　by　comparing　it　with　a　single-stage　thermal　storage　unit　(STSU),　focusing　on　the　alteration　of　heat　transfer　fluid　(HTF)　inlet　temperature　and　volume　flow　rate　to　analyze　the　heat　transfer　performance　of　the　cascaded　thermal　storage　unit　(CTSU).　Moreover,　the　assessment　of　CTSU　entails　the　evaluation　of　phase　change　material　(PCM)　melting　time,　charging　capacity,　charging　efficiency,　and　exergy　efficiency　under　typical　operating　conditions　for　various　PCM　length　ratios　and　different　PCM　melting　temperature　differences.　The　PCM　melting　time　inside　CTSU　is　reduced　by　25　%　compared　to　STSU　under　typical　operating　conditions　of　a　temperature　of　70　degrees　C　and　a　volume　flow　rate　of　1.5　L/min,　while　the　charging　efficiency　is　increased　by　1.09　%.　For　a　PCM　length　ratio　of　1:3,　the　CTSU　demonstrates　excellent　time　matching　and　achieves　a　maximum　charging　efficiency　of　84.56　%.　When　the　temperature　differential　of　PCM　melting　is　7　degrees　C　in　the　CTSU,　the　PCM　completes　melting　in　26　min,　reaching　a　maximum　charging　efficiency　of　86.10　%.