The　current　traceability　methods　for　electronic　medical　record　data　face　three　primary　challenges.　Firstly,　prevailing　data　privacy　protection　strategies　predominantly　rely　on　traditional　asymmetric　encryption　technology,　which,　however,　falls　short　in　achieving　fine-grained　access　control.　This　limitation　complicates　the　tracking　of　dynamic　data　sharing.　Secondly,　existing　encryption　approaches　often　employ　linear　encryption　for　single　processes,　resulting　in　slow　encryption　and　decryption　rates　for　large　storage　space　files,　such　as　medical　image　data.　Lastly,　a　substantial　heterogeneity　exists　among　blockchain　platforms　utilized　by　different　hospitals,　posing　obstacles　to　seamless　data　sharing　and　exchange　and　contributing　to　the　creation　of　data　silos.This　paper　proposes　an　innovative　electronic　medical　record　data　traceability　method　based　on　attribute　encryption　to　address　the　aforementioned　issues.　The　method　employs　attribute　encryption　to　regulate　ciphertext　access,　enabling　dynamic　sharing　of　private　data.　Simultaneously,　the　performance　of　traditional　attribute　encryption　schemes　is　enhanced,　and　a　fragment　algorithm　is　introduced　to　accelerate　the　encryption　and　decryption　processes　for　large　files.　Additionally,　a　blockchain　cross-chain　middleware　is　designed　to　facilitate　data　sharing　between　heterogeneous　blockchains.　©　2024　Copyright　held　by　the　owner/author(s).