ERECTA gene encodes a leucinerich repeat receptorlike Ser/Thr kinase. It participates in regulating morphogenesis of plant organs and plays an important role in the change of plant type and resistance to adversity. In the present study, pET21aCsERECTA, a prokaryotic expression vector with maltose binding protein tags was constructed and successfully expressed in E. coli BL21(DE3)．Expression conditions were optimized in the optimal temperature ,induction duration, and IPTG concentration．The fusion protein MBPCsERECTA was purified by nickel chelating chromatography and enzyme digestion was conducted by rTEV protease. The CsERECTA protein was obtained and it was used to prepare polyclonal antibody．The results showed that CsERECTA was expressed in the form of soluble and inclusion bodies in E. coli BL21(DE3), and a large number of proteins were soluble at low temperature. The optimal temperature,induction duration and IPTG concentration were 23 ℃,6 h and 0.5 mmol·L^-1, respectively．Western blot showed that the polyclonal antibody of CsERECTA has good specificity, because endogenous CsERECTA was detected. The successfully prepared polyclonal antibody can be used for further investigation, which establish the foundation for investigating the function of the CsERECTA gene in cucumber．