Abstract: 【Objective】 The formation mechanism of the diversity of Dendrobium flower patterns was explored through the combined analysis of miRNA and transcriptome sequencing，providing theoretical reference for in-depth exploration of the regulatory mechanism of Dendrobium flower development and breeding new varieties with ornamental value. 【Method】 Three Dendrobium species with high ornamental value and significant floral morphological differences， Dendrobium crepidatum Lindl. exPaxt., Dendrobium officinale Kimura & Migo and Dendrobium loddigesii Rolfe，were selected for miRNA and transcriptome sequencing. DEGSeq was employed to analyze gene expression differences among the 3 Dendrobium species，and miRNA-mRNA regulatory networks of the 3 Dendrobium species were constructed. 【Result】 From the transcriptome sequencing data，279，319 and 293 flower development related mRNAs were identified in Dendrobium crepidatum Lindl. exPaxt.，Dendrobium officinale Kimura & Migo and Dendrobium loddigesii Rolfe respectively. In Dendrobium crepidatum Lindl. exPaxt.，1364 miRNAs targeted 117 flower development related target mRNAs； in Dendrobium officinale Kimura & Migo，1615 miRNAs targeted 195 flower development related target mRNAs；and in Dendrobium loddigesii Rolfe，1360 miRNAs targeted 111 flower development related target mRNAs. Through the joint analysis of the miRNA-mRNA regulatory networks of 3 Dendrobium species，940 miRNA with significantly different expressions targeting 31 target mRNA related to flower development were finally screened out，including miR172-AP2/ AP2-3， miR5179-MADS16， miR168-NPR5/DCAF1， miR408-5GT/LOC110111162/ANS/FHA2/SPL8, miR528-YAB1/ SOC1/MADS6/GPAT6/VIL1 and miR166-MADS3/5GT regulation network. The above miRNA and mRNA together constituted regulation network of floral organ development of 3 Dendrobium species，and they mainly involved in biological processes such as the development of petals，sepals，flower organs，tissues，and the morphological and size development of stamens and pistils. 【Conclusion】 The floral development process in Dendrobium involves a complex miRNA-mRNA regulatory mechanism. Differentially expressed mRNAs and miRNA-mRNA regulatory networks in Dendrobium crepidatum Lindl. exPaxt.，Dendrobium officinale Kimura & Migo and Dendrobium loddigesii Rolfe are likely the primary factors contributing to their distinct floral morphologies of the 3 Dendrobium species. Key candidate miRNAs，including miR172，miR168，miR408，miR528 and miR166，participate in regulating multiple biological processes of Dendrobium floral development. Regulatory networks such as miR168-NPR5/DCAF1，miR408-5GT/LOC110111162/ANS/FHA2/SPL8， miR528-YAB1/SOC1/MADS6/GPAT6/VIL1 and miR166-MADS3/5GT provide new directions for molecular research on floral organ development in Dendrobium.