Myoglobin（Mb） was immobilized on glassy carbon electrode（GCE） surface by konjac glucomannan（KGM）.Mb entrapped in the KGM film undergoes fast direct transfer-electron reactions in aqueous-organic solvents mixtures.The formal potential(E

0

=-0.434 V) indicate the redox of MbFe（Ⅲ）/（Ⅱ） couple.The E

0

is linearly dependent on solution pH（redox Bohr effect）

indicating the electron transfer of MbFe（Ⅲ）/（Ⅱ） redox couple companied with the transfer of proton.The electrochemical properties of the Mb almost keep unchanged in aqueous-organic solution comparing with pure aqueous one

suggesting that water pools in KGM hydrogel play an important role in preventing the change of conformation and inactivity of proteins from polar organic solvents.The immobilized Mb is able to dehalogenate haloethanes（hexachloroethane

pentachloroethane

tetrachloroethane） which is cytochrome P450-like activity.Stability and reproductivity of the modified electrode make it possible to determine these substances.