Although enzyme catalysis has many advantages such as green, high efficiency and so on, the industrial application of enzyme is often hampered by a lack of long-term operational stability and difficult to re-use. These drawbacks can generally be overcome by immobilization of the enzyme on a solid carrier. However, the immobilized enzyme reactor often can not remain all the initial catalytic activity due to the enzyme shedding during reuse, change of conformation and the difficulty for substrates to access the active site of enzyme in the carrier, etc. The contradiction between catalytic activity and stability of biological enzyme molecules supported on solid phase carriers has become a bottleneck in the design and preparation of immobilized enzyme reactors. Therefore, it is a challenging task to construct an immobilized enzyme reactor with both high catalytic activity and high stability. In this work, aluminum-based metal-organic framework (Al-MOF)-derived hierarchical porous Al₂O₃ (MHAl₂O₃) was prepared by the self-sacrificial template strategy and functionally modified with “polydopamine (PDA)” bionic membrane for entrapping horseradate peroxidase (HRP). The pore size was regulated by changing the calcination temperature of precursor. The influence of channel confinement effect of the carrier on the catalytic activity of the enzyme reactor was discussed, and the thermal stability and reusability of the HRP@PDA@MHAl₂O₃ was significantly improved. After 1 h at 70 ℃, 98.5% of the catalytic activity of HRP@PDA@MHAl₂O₃ could be maintained. After 10 times of reuse, 90.9% of the catalytic activity was still maintained. In order to analyze the structure-activity relationship of the enzyme reactor, the interaction between enzyme and substrate in the reaction catalyzed by HRP@PDA@MHAl₂O₃ was studied by means of enzyme kinetics and thermodynamic parameters, which showed that the affinity and specificity of the enzyme to the substrate were improved. When the enzyme reactor was applied to the catalytic degradation of aniline aerofloat in simulated wastewater, the degradation rate of 40 mg•L^-1 substrate in 30 min reached 82.7% under the best reaction conditions.