The PCR technique was used to amplify the exon-specific segments of Zmrr3 gene from Luyuan 92 of maize genome, and the Expression Vector with RNAi expression pCAMBIA303+RNAi +2F was constructed with the sequence of the target fragment, which contains Hygromycin, kanamycin kanamycin and GUS slective gene. It can be used to study the relation between cytokinins and phyllotaxis of Maizet in molecular mechanism.