Biomethane is a kind of renewable fuel produced after the biogas is purified by desulfurization, decarbonization and dehydration. Its composition and calorific value are almost same as natural gas which means biomethane is a promising renewable energy to be used as vehicle fuel or injected to the natural gas grid. To enable the efficient use of biomethane in these applications the biogas must be cleaned and upgraded. Removal of H2S and CO2 are necessary processes for the commercial utilization of biogas and a number of techniques for transformation of biogas to biomethane have been developed. In this review, the main desulfurization and decarbonization technologies for the production of biomethane were systematically reviewed with their upgrading efficiency, methane (CH4) loss, energy requirement, environmental effect, development and industrialization. The technologies for the removal of H2S discussed in this work including absorption (physical and chemical), adsorption and biodesulfurization. And the technologies for the removal of CO2 including absorption (physical and chemical), pressure swing adsorption (PSA), membrane separation, cryogenic separation and the emerging biological methanation processes were discussed. Process flow and mechanism of each technology, as well as commercialization examples were introduced in detail with emphasizing their critical points and analyzing their advantages and deficiencies. Particularly, the review emphasized that biodesulfurization and biological methanation possess significant advantages over conventional physical/chemical technologies for biogas upgrading. Main advantages were that biotechnologies operated at normal temperatures and pressures, without the use of toxic complex chemicals, especially the biological removal of H2S in biogas had undergone a rapid development over the past 20 years and was nowadays commercially available and implemented in full scale facilities. The current challenges and future perspectives of biogas desulfurization and decarbonization processes were also discussed. Finally, the aim of the review was to provide process references for the research and industrial development of biomethane.