In this paper,1-acetoxy-2-(acyloxymethoxy)-3-chloropropane was synthesized with epichlorohydrin as the starting material,and then condensed with diacetylguanine to obtain monocloganciclovir condensate.The structure was confirmed and the purity was detected by HPLC,1 H1 NMR and LC-MS.The results showed that the reaction conditions were mild and the purity of the prepared impurities was high,which could be used as the impurity reference substance for the quality control of ganciclovir.