In the basis of transcriptomic analysis，a novel AGL6 gene was cloned from Paeonia suffruticosa cultivar ‘Luoyanghong’ by RTPCR technique, which contained an open reading frame of 732 bp encoding a putative protein of 244 amino acids. (1) Protein sequence analysis showed that the gene have highly conserved MADS MEF2 Domain, K Domain, typical AGL6 I and AGL6II Motif，which belongs to the MADS box gene family and named as PsAGL6 (GenBank No: MF563611). (2) Homology analysis showed that PsAGL6 protein was high identity with VvAGL6 from Vitis vinifera (79%). (3) qRTPCR demonstrated that PsAGL6 was expressed in all tissues, little expression in vegetable tissues, but high expression in the floral organs. Expression of PsAGL6 was highest in sepal, petal and carpel followed. In petal of different flower type of 4 tree peony cultivars, qRTPCR results showed that the expression of PsAGL6 had significant difference between different cultivars. The expression of PsAGL6 was the highest in the flower type of rose. In conclusion, PsAGL6 gene involves the formation of floral organs. These results provided help for revealing the molecular mechanism of floral organ development.