In this study, a multiscale computational fluid dynamics (CFD) coupled model comprising a macroscopic fluid flow model and microscopic mass transfer-biodegradation kinetics model is developed to obtain a comprehensive understanding of the mass transfer-biodegradation process of H2S in biofilms and biotrickling filters (BTFs). The developed CFD coupled model is calibrated and validated using the experimental data of H2S concentration profiles in a pilot-scale BTF. Using the proposed model, the dynamic removal process of H2S is investigated. A sensitivity analysis of the model parameters is then performed, and mass transfer and biodegradation kinetics characteristics are obtained. The validated model is applied to explore the effects of biofllm thickness and area on macroscopic deodorization performance. A widespread application of the established CFD coupled model can consequently be expected to optimize the design of industrial-scale BTFs.