Provided are a PVA membrane immobilized enzyme and a preparation method therefor. The PVA membrane immobilized enzyme comprises a PVA porous membrane and an enzyme entrapped on the PVA porous membrane. The PVA porous membrane is a three-dimensional structured PVA porous membrane. The enzyme is any one selected from transaminase, D-lactate dehydrogenase, cyclohexanone monooxygenase, ketoreductase, alkene reductase, nitrilase, ammonia lyase, amino acid dehydrogenase, imine reductase, alcohol dehydrogenase, ammonium formate dehydrogenase, glucose 1-dehydrogenase and mutants thereof. The three-dimensional structured PVA porous membrane is used as a carrier to immobilize an enzyme in an entrapment manner. The entrapment and immobilization process is simple, conditions are mild, and the specific surface area is large. After entrapping and immobilizing the enzyme in the PVA porous membrane, the enzyme is stable, and cannot be easily leached out in the process of use. The porous structure of the PVA porous membrane used can better transmit reactants and products, is suitable for use in continuous flow biochemical catalysis, and has wide applicability to enzymes.