In this experiment,PCR and RACE methods were used to clone and bioinformatics was used to analyze the ethylene insensitive 2 (EIN2) gene of Oncidesa Gower Ramsey. The qRTPCR technique was used to analyze the different tissue sites and different flowering stages of Oncidesa. The results showed that: (1) The EIN2 gene of Oncidesa, named OnEIN2 (MH497388) was successfully cloned; the cDNA of OnEIN2 fulllength was 4 177 bp, contains a 3 879 bp open reading frame（ORF）, encoding 1 292 amino acids, the noncoding region of 3′ and 5′ were 208 bp and 90 bp. (2) Bioinformatics analysis showed that OnEIN2(molecular formula: C₆₄₀₆H₉₉₈₈N₁₆₇₀O1897S₄₇) was an unstable hydrophobin protein containing a transmembrane domain; the molecular weight of the protein was 142.22 kD and the theoretical isoelectric point was 5.80. Multiple sequence alignment and phylogenetic analysis showed that the similarity of OnEIN2 was highly similar to EIN2 in Dendrobium catenatum (up to 81.98%), and the genetic relationship between them was the closest. (3) Quantitative realtime PCR showed that OnEIN2 expresses in roots, stems, leaves and flowers; with the highest expression level in flowers and the lowest level in stems, while the expression level was the highest in different flowering stages during the blooming period, followed by senescence stage. This study showed that OnEIN2 may play an important role in flowering and senescence.