NOVELTY - Determining amount of desulfurization agent-based on in situ desulfurization of biogas, comprises (i) adding desulfurization agent and biogas fermentation broth, respectively, and preparing at least three different concentrations of desulfurization agent and biogas fermentation broth, carrying out parallel experiments of biogas, and recording concentration of hydrogen sulfide during the production of biogas based on parallel experiments; and (ii) adding desulfurization agent to fermentation broth, based on relationship between curve and target concentration of hydrogen sulfide gas.    USE - The method is useful for determining amount of desulfurization agent-based on in situ desulfurization of biogas (claimed).    ADVANTAGE - The method has simple operation procedure, can accurately determine the amount of desulfurization agent utilized in the process, and is economical, and prevents the excessive utilization rate of chemicals causing pollution.    DETAILED DESCRIPTION - Determining amount of desulfurization agent-based on in situ desulfurization of biogas, comprises (i) adding a desulfurization agent and a biogas fermentation broth, respectively, and preparing at least three different concentrations of desulfurization agent and biogas fermentation broth, carrying out parallel experiments of biogas, and recording the concentration of hydrogen sulfide during the production of biogas based on parallel experiments, and difference in concentration of hydrogen sulfide and desulfurization agent added during the production of biogas, and calculating the amount of desulfurization agent added by a formula as given in the specification, and calculating the amount of hydrogen sulfide reacting with desulfurization agent, and difference in concentration hydrogen sulfide reacted with desulfurization agent to the initial amount of the desulfurization agent, to obtain fermentation broth-containing desulfurization agent, where the initial concentration of fermentation broth- containing desulfurization agent is 0-32 mol/m3 based on relation curve between the concentration of fermentation broth-containing desulfurization agent and hydrogen sulfide concentration versus the concentration of hydrogen sulfide in the production of biogas fermentation broth and the desulfurization agent; and (ii) adding desulfurization agent into the fermentation broth, based on the relationship between the curve and the target concentration of hydrogen sulfide gas.