The reaction mechanism of intermediate 3，3′-Bis（1，2，4-oxadiazole）］-5，5′-diyldimethanol acetate （BODM） hydrolyzed to 3，3"-Bi（1，2，4-oxadiazole）-5，5"-diyldimethanol （BOD） was investigated by theoretical calculation. The synthesis process was optimized by single factor experiment and orthogonal experiment. The structure and properties of BOD were analyzed by XRD， FTIR， NMR and DSC. It was found that the reaction mechanism was the lone pair electrons in BODM —［O］— formed an OH…O hydrogen bond with H in H₂O， then the O—C bond in —［O］—［C═O］—broke， and the H and OH bonds in H2O formed —OH and —COOH group in —［O］— and —［C═O］—， respectively. and found that the crystal of BOD belong to the monoclinic system， the space group is C2/c， the cell angle α=90°， β=105.361（7）°， γ=90°， the cell volume v=774.9（2） A³， the density ρ=1.698 g·cm^-3. The melting point and decomposition peak temperature were 197.18 ℃ and 278.37 ℃， respectively. The results of single factor experiment showed that with the increase of reaction time and solvent， the yield of BOD increased at first and then became stable. With the increase of reaction temperature， the yield of BOD increased slowly and then decreased rapidly. With the increase of material ratio， the yield of BOD increased first and then decreased. In addition， the optimal process conditions were obtained by orthogonal experiment： BODM hydrolyzed in potassium carbonate methanol solution at 45 ℃ for 8 h， in which the molar ratio of BODM to potassium carbonate was 15∶1， and the yield was 94%. This study provides theoretical basis and experimental reference for scaling up and large-scale production of BOD.