The　evolution　of　the　microstructure,　microchemistry　and　magnetic　properties　of　the　Sm(CobalFe0.28-CuyZrx)(7.6)　magnets　with　different　Zr　and　Cu　contents　was　investigated.　It　is　found　that　the　coercivity　of　the　Sm(Co,Fe,Cu,Zr)z　magnets　is　sensitive　to　Zr　content.　The　deficiency　of　Zr　content　causes　heterogeneity　of　Cu　and　Fe　distributions,　while　an　excessive　Zr　content　leads　to　the　formation　of　a　SmCoZr　impurity　phase.　The　cellular　structure　and　distribution　of　Cu　concentration　gradient　between　the　cell　boundary　phase　and　cell　phase　are　destroyed　by　inappropriate　Zr　content,　which　results　in　a　reduction　of　coercivity.　The　Cu　concentration　difference　between　the　cell　boundary　phase　and　cell　phase　increases　with　increasing　Cu　content.　The　coercivity　of　the　Sm(CobalFe0.28CuyZr0.02)(7.6)　magnets　increases　from　10.4　to　25.4　kOe　for　y　=　0.05　and　y　=　0.07.　However,　the　excess　of　Cu　element　destroys　the　cell　boundary　phase　and　enlarges　the　cell　size,　resulting　in　a　significant　decrease　of　squareness　and　energy　density.　The　optimum　performance　(remanence　of　11.4　kG,　coercivity　of　25.4　kOe,　maximum　magnetic　energy　product　of　30.4　MGOe)　was　obtained　for　the　Sm(Co0.63Fe0.28Cu0.07Zr0.02)(7.6)　magnet.　(C)　2020　Chinese　Society　of　Rare　Earths.　Published　by　Elsevier　B.V.　All　rights　reserved.