Disclosed are a modified epoxy resin immobilized enzyme, a preparation method therefor and an application thereof. Herein, the preparation method includes the following steps: modifying an epoxy resin, adding a polyethyleneimine to a modified epoxy resin for further modification, and then adding an enzyme to be immobilized and a glutaraldehyde for immobilization, to obtain the modified epoxy resin immobilized enzyme. The epoxy resin is modified, the polyethyleneimine is added to the modified epoxy resin for the further modification, and an aldehyde group in the resin and an amino group in the polyethyleneimine are covalently bound to each enzyme, then it is activated by the bifunctional reagent glutaraldehyde. In this way, a steric resin arm is increased, to form a network structure, it may be more easily bound to the enzyme by covalent binding, and the enzyme load may also be improved because the steric inhibition is reduced.