In the actual operation of biogas purification technology, chemical or biological methods are often used to remove H2S from biogas. The two desulfurization methods have their own advantages and disadvantages. It is more practical to adopt chemical desulfurization method for small biogas projects; biological desulfurization method should be adopted for large and medium-sized biogas projects; biological chemical combined process is an effective scheme for treating biogas with high H2S concentration. Users can choose according to their actual needs.