Reference materials are helpful to the evaluation of the performance of laboratories and for the quality control of analytical procedures.However,reference materials containing veterinary drugs in royal jelly powder are not available.A method regarding the preparation of reference material for metronidazole residue in royal jelly powder was presented.About 400 packages of royal jelly powder were obtained from the non-compliant sample by the procedure of homogenation,cryodesiccation and packaging.The homogeneity,short-term stability and long-term stability were examined by F-test or t-test,and all of them could meet the requirement for reference material at a confidence level of 95%.The value of metronidazole in this sample was certified through the collaborative analysis program by 8 expert laboratories at home and abroad using different sample preparation procedures,but exclusively LC-MS/MS method.The data were evaluated by Grubbs test and Cochran test.Meanwhile,the uncertainty due to sample homogeneity,short-term and long-term stabilities and variabilities in the characterization procedure was estimated.