The present disclosure relates to a method for preventing agglomeration in a mixture of xylitol and calcium aspartate. The method includes the following steps: first adjusting and measuring water activities of xylitol particles and calcium aspartate particles; then mixing the calcium aspartate particles with a water activity of 0.50-0.52 with the xylitol particles with a water activity of 0.48-0.56, or mixing the calcium aspartate particles with a water activity of 0.52-0.58 with the xylitol particles with a water activity of 0.50-0.60, or adding maltitol particles with a weight ratio of 5%-20% to the xylitol particles to a mixture of the calcium aspartate particles and the xylitol particles. By controlling the water activities of the xylitol particles and calcium aspartate particles, or by adding maltitol in the mixture, agglomeration of the mixture can be effectively prevented, and the method is applicable to mixtures of various xylitol raw materials.