A process of alkaline biological desulfurization was used to treat biogas produced by a biomass comprehensive treatment project. The desulfurization effect and operation cost of the project were analyzed. The results showed that when the gas volume was 25200~52200 Nm3/d, the sulfur loading was 56.05~111.45 kgS/d and the H2S concentration of inlet was 1909~2882 mg/Nm3, the outlet concentration of H2S was 8~58 mg/Nm3 which met the relevant requirements of biogas power generation technology criterion(NY/T 1704—2009). The average desulfurization rate was 98.7%. The treatment capacity of a single set of biogas desulfurization equipment was 48000 Nm3/d and the cost of materials and power was 0.027 yuan/Nm3.