Enzymes with well recognized high chemo-, regio-, and enantio-selectivity are powerful molecules that can efficiently catalyze the production of a variety of chemicals and pharmaceuticals. Undoubtedly, there is a tremendous need for enzymes as biocatalysts used in green chemistry and pharmacy. However, there are limited successes of the industrial applications of enzymes presently due to their poor suitability for most commercial uses. To enable the enzymatic process to substitute the traditional chemical process, most of the natural enzymes must be tailor-made to improve their properties in vitro such as catalytic activity, stability, or substrate scope. In this review, we will discuss current advances in molecular redesign and construction of new biocatalysts by rational and irrational strategies, especially in conjunction with the computational design for rapidly generating new types of catalytic function. Three aspects for enzyme redesign and construction are presented. First one concerns the improvement of the catalytic performance, such as catalytic efficiency, stability, and optimal pH bias. Second enables the optimization of the substrate profiles. Third focuses on generating the novel biocatalysts by de novo design.