The invention discloses a dehydration method for an ether solvent. The method comprises the following steps: adding the ether solvent into a dehydration agent for dehydration reaction, and after reaction, performing distillation to obtain an anhydrous ether solvent, wherein the dehydration agent is a condensation product of a Grignard reagent and ketone/aldehyde. According to the method, halogenated magnesium alkoxide generated by condensation reaction of the Grignard reagent and the ketone/aldehyde is adopted as the dehydration agent for the ether solvent, so that the utilization rate of the halogenated magnesium alkoxide is increased, dehydration of the ether solvent and synthesis of alcohol are implemented at the same time, the dehydration reaction process is mild, no high-risk byproduct such as H2 is generated, and the production cost can be reduced better.