The performances of two identical biofilters, filled with a new composite packing material (named CM-5) embedded with functional microorganisms or sterilized CM-5 without microorganisms, were investigated for H₂S treatment. Running parameters in terms of microbial counts, pressure drops, and inlet and outlet H₂S concentrations were measured. The results show that the microbial count of the CM-5 was approximately ×10⁵ CFU/g before being filled into the biofilter, while that of the sterilized CM-5 was negligible. The functional microorganisms embedded in CM-5 adapted to the environment containing H₂S quickly. In most cases, pressure drops of the CM-5 biofilter were slightly higher than those of the sterilized CM-5 biofilter when the gas flow rate was 0.6–2.5 m³/h. The maximum elimination capacity (EC) of the CM-5 biofilter in treating H₂S could reach up to 65 g/(m³·h) when the loading rate (LR) was approximately 80 g/(m³·h). If the LR was much higher, the measured EC showed a slight downward trend. The experimental ECs of biofilters were fitted by two typical dynamic models: the Michaelis-Menten model and the Haldane model. Compared with the Michaelis-Menten model, the Haldane model fit the experimental ECs better for the two biofilters because of the presence of the substrate inhibition behaviour.