Abstract: The gaseous plant hormone ethylene regulates a variety of developmental process and biotic and abiotic stress response in plant. During the past decade, molecular genetic studies on the model plant Arabidopsis have established a linear signal transduction pathway from signal perception on the endoplasmic reticulum membrane to transcriptional regulation in the nucleus. Ethylene receptor family in Arabidopsis consists of five components, including ETR1, ERS1, ETR2, ERS2 and EIN4, at least one of which, ETR1, was reported to localize on endoplasmic reticulum, and negatively regulates ethylene response by forming a complex with Raflike kinase CTR1. Downstream of CTR1 are EIN2 and EIN3/EILs, which positively regulate ethylene response.In the absence of ethylene signal, EIN3 is quickly degraded through an ubiquitin/26S proteasome pathway mediated by two F-box proteins, EBF1 and EBF2. EIN5, a 5’→3’ exoribonuclease, antagonizes the negative feedback regulation on EIN3 by promoting EBF1 and EBF2 mRNA decay. Despite the recent advances on the understanding of plant response to ethylene, many aspects of the ethylene signaling pathway remain unknown, especially the biochemical nature and the regulatory mechanisms of key pathway components, as well as the molecular basis of various interactions between the ethylene response pathway and other signaling pathways. In the coming years the research in this fast advancing field might provide much of the needed answers to these problems.