Staphylococcus epidermidis (S. epidermidis) is an opportunistic pathogen that colonizes on the surface of human skin and in mucous membranes. It can form biofilms by adhering to indwelling medical devices, often causing biofilm-associated infection. Two-component signal transduction systems (TCSs) play an important role in modulating biofilm formation in bacteria. However, regulation mechanisms of TCSs in S. epidermidis are still poorly understood. In this study, the expression of response regulator ArlR of arlRS TCS in S. epidermidis growth phases was investigated. The prokaryotic expression plasmid pET28a-arlR was constructed, and ArlR protein was expressed and purified. The purified ArlR was used to immunize mice for inducing anti-ArlR antibodies. The titers of anti-ArlR in the immune sera were over 1:100000, as determined by immune dot blot technique. ArlR expression in the different growth phases in bacteria was detected by Western blot analysis. Results showed that the expression level of ArlR was lowest at 2-hour culture and highest at 4-hour culture, and declined at 6-hour and 10-hour cultures. Western blot analysis results were confirmed by the transcriptional levels of arlR determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. It would help to get additional insight in to arlRS TCS regulation functions in the formation of biofilms in S. epidermidis.