In this study, a series of rare earth monosubstituted Dawson-type polyoxometalates were synthesized for highly effective removal of hydrogen sulfide (H2S). The unused, used and regenerated polyoxometalates were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results confirmed that K17[Pr(P2Mo17O61)2] could maintain a complete Dawson-type structure even after absorption and regeneration. H2S absorption study showed that K17[Pr(P2Mo17O61)2] had the remarkable desulfurization and regeneration capabilities. Optimization experiments showed that K17[Pr(P2Mo17O61)2] under the condition of low H2S concentration or high dosage of K17[Pr(P2Mo17O61)2] had the ideal desulfurization performance. An appropriate temperature of 25°C is necessary for high removal efficiency. The optimum pH value for desulfurization is 6.8. The desulfurization product was proved to be SO42–.