A plate type biotrickling filters (plate type-biotrickling filter, PTBTF) in which three layers are separately sprayed by nutrient solution of pH 2.5, 4.5 and 6.5, relatively, was designed for H2S removal at the start-up and steady states. The biofilm formation of PTBTF was completed within 14 d, and the removal efficiency of 100% was achieved at the inlet H2S concentration of 188.6 mg x m(-3). Afterwards, H2S removal efficiency remained above 99% with the inlet concentration between 100 mg x m(-3) and 1 000 mg x m(-3) and empty bed residence time (EBRT) between 28 s and 4 s. When removal efficiency was 90%, the maximum elimination capacity of PTBTF increased with EBRT (3.3-6 s), e. g. 1 019.0 g x (m3 x h)(-1) for EBRT 6 s. The elimination capacity of the upper, middle and lower layer varied with the inlet H2S loading. It was found that the microorganisms onto the packing carriers in upper, middle and lower layers increased significantly at the start-up state, and reached 1.29 x 10(7), 5.47 x 10(8), and 1.07 x 10(9) cells x g(-1), respectively, in 125 d by the means of fluorescence staining. The bacilliform and filamentous microorganisms were the dominants in the upper and lower layer, respectively, observed by scanning electron microscopy. The biological community analysis by denaturing gradient gel electrophoresis was also conducted in this study. The main products of SO4(2-) and sulfur were determined for H2S degradation.