The invention relates to a preparation and using method for a tannin germanium depositing agent and belongs to the technical field of non-ferrous metallurgy wet process germanium beneficiation. The preparation method comprises the steps that weighed tannin is added into a first-level dissolving tank and added with water with the temperature being 25-35 DEG C to be subjected to constant-temperature dissolving and continuous stirring; in the first-level dissolving tank process, the agglomerating large-particle (the particle size is larger than 1 mm) tannin is controlled and discharged into a storage tank to be subjected strengthening dissolving through the first-level dissolving tank liquid level and returns to the first-level dissolving tank; the mixed liquid which completes first level dissolving is added into a second-level dissolving tank and continuously stirred and dissolved; the mixed liquid which completes second level dissolving is added into a temperature regulating tank, the temperature is adjusted, and the preparation process of the tannin germanium depositing agent is completed; and the consumption multiple of the tannin germanium depositing agent is calculated, and the tannin germanium depositing agent is added into a zinc sulfate solution containing germanium to be subjected to germanium depositing treatment. According to the preparation and using method for the tannin germanium depositing agent, the tannin is dissolved and diluted from low temperature step by step to high temperature grading, condensation, agglomerating and high-temperature adhesion bond failure of the tannin are effectively avoided, the utilization rate of the tannin is increased, and the cost is reduced.