Abstract: Taking Chrysanthemum ‘Jinba’and Arabidopsis thaliana as experimental materials,the precursor sequence and secondary structure,evolutionary relationship,expression pattern,growth and development function of Chrysanthemum MIR156cgene were studied by bioinformatics and molecular biology methods,in order to provide reference for the molecular mechanism of Chrysanthemumgrowth and development.The results showed that the sequence length of the cloned Chrysanthemum MIR156c was 212bp.cmio-MIR156ccould form a typical stem-loop structure,which was specific at the 11th position of the mature sequence.Compared with the reported Chrysanthemum miR156,the 14th base was also different,and evolutionary analysis showed that the relationship was far.The mature sequence of miR156was highly conserved,and the rest of its precursor sequence was quite different,especially the hairpin region.The expression of cmo-MIR156c was different in various organs of Chrysanthemum,with the highest expression in roots and tubular flowers.The heterologous expression of cmo-MIR156cin Arabidopsis changed the number of rosette leaves,the number of branches and flowering time,and affected the development of flowers and siliques.