Polyacrylonitrile　ultrafiltration　membranes　have　been　widely　used　in　many　separation　processes.　In　this　paper,　horseradish　peroxidase　was　immobilized　onto　polyacrylonitrile　ultrafiltration　membrane　by　crosslinking　with　glutaraldehyde.　The　immobilized　enzyme　possessed　a　protein　loading　of　0.025　mg/cm2membrane　and　a　specific　activity　of　105　U/mgprotein　(105　μmol/min/mgprotein).　The　initial　modified　and　immobilized　membranes　were　observed　using　SEM　and　FTIR.　Potential　applications　of　HRP　membranes　were　investigated　in　the　removal　of　phenol　through　oxidation　with　the　addition　of　hydrogen　peroxide.　The　optimum　pH　of　the　immobilized　enzyme　was　determined　to　be　6.0,　and　the　optimum　hydrogen　peroxide　concentration　to　be　30　mmol/L.　Almost　100　%　removal　of　phenol　(1　∼　10　mg/L)　from　water　was　achieved　by　HRP　membranes.　For　high　concentrated　solutions,　successive　cycles　were　successfully　used　to　improve　the　degree　of　phenol　oxidation.　Furthermore,　the　immobilized　horseradish　peroxidase　was　operationally　stable.　These　results　suggest　that　the　HRP　membrane　has　promising　applications　for　the　removal　of　phenol.　©　2016　Canadian　Society　for　Chemical　Engineering