The invention discloses a method for maintaining yeast activity, and belongs to the technical field of fermentation engineering microorganisms. The yeast is stored through the trehalose solution, andthe activity of the yeast is kept. Beer yeast paste is stored at 25 DEG C for 4 days by using the trehalose solution with the concentration of 50 mmol/l, so that the ATP content in yeast cells is increased by 2 times or more, the tolerance of the beer yeast under osmotic pressure stress and oxidative stress is improved, and the maintenance of the cell viability in the yeast storage process is facilitated. Compared with a control group, the yeast stored in 50 mmol/l and 100 mmol/l trehalose solutions has better growth capacity on an osmotic pressure stress plate culture medium and a hydrogen peroxide stress plate culture medium, and the effect can be achieved under the protection of the 50 mmol/l trehalose solution. The method is simple and effective, and has important significance on storage of beer yeast in beer production.