This　study　examines　the　impact　of　varying　Be　contents　on　the　evolution　of　secondary　electron　emission　(SEE)　properties.　Through　microscopic　characterization　of　the　microstructure　before　and　after　activation,　it　was　determined　that　the　phase　composition　was　alpha(Cu)　phase　and　eutectic　structure　(alpha(Cu)　+　gamma).　The　findings　indicate　that　as　the　Be　content　increased　from　2.8　wt.%　to　3.8　wt.%,　the　proportion　of　heterogeneous　structures　increased　and　the　distribution　became　more　uniform.　Meanwhile,　the　number　of　heterogeneous　structure　interfaces　between　alpha(Cu)　phase　and　gamma　phase　increased,　and　there　were　a　large　number　of　mismatch　dislocations　at　the　interfaces,　which　served　as　short-circuit　diffusion　paths　for　Be　elements.　Be　elements　were　more　easily　able　to　diffuse　outward　through　the　interface　to　form　a　uniform　BeO　film,　thereby　increasing　secondary　electron　yield　(SEY).　In　addition,　the　density　of　mismatch　dislocations　near　the　interface　was　high,　promoting　the　formation　of　grain　boundaries,　which　provided　more　diffusion　pathways,　allowing　Be　elements　to　diffuse　outward　more　easily,　thereby　generating　a　uniform　BeO　film　with　increased　SEY.　This　study　holds　significant　implications　for　augmenting　the　SEY　of　Cu-Be　dynode　electrodes　used　in　photomultiplier　tubes　(PMTs).