Rab family proteins play a crucial role in regulating vesicular traffic in eukaryotic cells. EoRab43 is an atypical Rab gene identified in Euplotes octocarinatus. In order to understand the function of EoRab43, the 153bp fragment of the 3'-end of EoRab43 gene was subcloned into expression vector pGEX-6P-1, and the recombinant plasmid pGEX-EoRab43(153bp) was transfered into E.coli BL21 (DE3) to express the fusion protein. The fusion protein GST-EoRab43C was expressed and purified by affinity chromatography. BALB/c mice were immunolized by purified GST-EoRab43C. The titer of anti-EoRab43C polyclonal antibody was detected by indirect ELISA assay and the specificity of the antibody was detected by Western blot. Immunofluorescence experiments were performed using anti-EoRab43C antibody in the cells of Euplotes. The results showed that EoRab43 displayed a punctuate pattern in the cytoplasm around the macronuclear chromosome of Euplotes.