Abstract: The waste liquor produced in maltol production process contains basic magnesium chloride,which can cause pollution and waste of resources in case of direct emission.In order to reduce environmental pollution and to prepare high value-added magnesium hydroxide product,basic magnesium chloride-contained waste liquor of maltol production was acidified and decolorizated.Then magnesium in the waste liquor was recycled by ammonia method to produce magnesium hydroxide.The product was characterized by SEM,XRD,and specific surface area analyzer etc..The results indicated that the sample was a little thick and lamella-like with perfect morphology and good dispersibility.This process made the waste into valuable product and reduced the emission of pollutants. 