The present disclosure provides a preparation method of rumen protected glucose, comprising the following steps: (1) preparing glucose into a pellet and drying (2) fluidizing the pellet in a fluidized bed after drying and (3) coating melted aliphatic alcohol and/or saturated fatty acid onto the surface of the pellet located in the fluidized bed to obtain a rumen protected bypass glucose particle. The prepared rumen-protected glucose could go through the rumen of ruminant effectively and the availability of coating layer in ruminant increases, making the coated glucose be released completely and fully utilized by ruminant, so ketosis or subclinical ketosis and fatty liver disease of the ruminants in perinatal stage could be prevented and reduced effectively, the postpartum weight loss could be reduced, and the cycle conception rate and the milk yield could be increased.
