Abstract: Borax was employed to react with slaked lime in water,and resultant mixture was then washed and filtrated to obtain calcium metaborate hexahydrate(CaO·B2O3·6H2O).Based on experiments,suitable process parameters were obtained,namely,m(B2O3)/m(CaO) of reactive raw materials was about 2.2∶[KG-*2]1;volume to mass ratio of liquid to solid was about 2.76 mL/g;reaction temperature and time were 35 ℃ and 8~10 h,respectively.Mass fractions of B2O3 and CaO in the product have reached 29%～31% and 23%～25% respectively and mass fraction of Na2O was less than 0.5%.XRD and TG-DTA analysis indicated that the product was calcium metaborate hexahydrate,and SEM analysis showed that the product was irregular hexagon long-and-narrow crystal.