Abstract: SAURs（Small auxin-up RNAs）are the early auxin-responsive genes，which play critical roles in regulating plant growth and development. In the present study，we identified the members of SAUR gene family in cucumber（Cucumis sativus）and analyzed their evolution，gene structure，tissue-specific transcription patterns，and responses to light intensity，temperature，and water potential. A total of 73 CasSAUR genes were identified and they were distributed onto the 7 chromosomes with 60% genes appearing in 2 clusters. The phylogenetic tree indicated that CsaSAURs could be further divided into 8 subfamilies and each of subfamily included a range of genes. The cis-acting elements，responding to IAA，ABA，GA，JA，SA，drought，low temperature，and mechanical damage，were identified by analyzing the promoter sequence of CsaSAURs. The members of CsaSAUR gene family exhibited different expression patterns and some of them can be activated or repressed by low light，high temperature，and high water potential. Among the 18 CsaSAURs highly expressed in hypocotyl，only CsaSAUR15 is up-regulated by the three environmental factors：low light，high temperature and high water potential.

Key words: cucumber, SAUR, gene expression, phylogeny analysis