[Objective] To enhance the stability of serine carboxypeptidase during enzymatic hydrolysis and expand its industrial applicability, the author employed rational design and immobilization technology to develop efficient and stable enzymatic catalysts in view of the easy deactivation of this enzyme. [Method] On the basis of the serine carboxypeptidase Y (CPY) derived from Aspergillus oryzae M30011, single mutant enzymes M517R, I464R, and Y271R and the triple mutant enzyme M517R/I464R/Y271R were designed. These mutant enzymes were then prokaryotically expressed in Escherichia coli and subjected to enzyme activity assays. Subsequently, the mutant enzyme with the highest activity was immobilized with covalent organic framework materials (COFs), yielding the composite designated as COFs@mutant enzyme. The free mutant enzyme and the COFs@mutant enzyme were systematically evaluated in terms of the pH stability, thermal stability, half-life, and reusability. In addition, with rice bran protein as the substrate, the hydrolysis effect of the COFs@mutant enzyme combined with alkaline protease (AP) was investigated. [Result] The four mutant enzymes were successfully expressed and purified, with the triple mutant M517R/I464R/Y271R exhibiting the highest enzyme activity (1 069.54 U/mg). Therefore, the triple mutant enzyme M517R/I464R/Y271R was immobilized with COFs (COFs@triple mutant enzyme).Compared with the free triple mutant enzyme, COFs@triple mutant enzyme demonstrated strong stability across wide ranges of pH and temperature, with a half-life extended to 498 min and the relative enzyme activity of approximately 50% after 6 reuse cycles. The results of the enzymatic hydrolysis experiment showed that the Fischer ratio (F-value) of the oligopeptides prepared from rice bran protein by AP combined with COFs@triple mutant enzyme was 34.01, far exceeding the preparation threshold (>20), indicating the good application potential of this combination in the preparation of oligopeptides. [Conclusion] The synergistic strategy of mutant enzyme design and immobilization technology significantly enhanced the industrial applicability of serine carboxypeptidase, providing a new direction for the production of functional oligopeptides and the optimization of industrial enzyme catalysis efficiency, and demonstrating broad application prospects.