There has been an accumulation of evidence to suggest that Rab18 is implicated in lipid droplet trafficking. However, the role of Rab18 GTPase in regulation of lipid metabolism in Clonorchis sinensis is unknown yet. In order to shed light on the specific and vital targets that are for Clonorchis sinensis treatment and control, a gene encoding Rab18 was isolated from Clonorchis sinensis adult cDNA. Recombinant CsRab18 was expressed and purified from Escherichia coli. CsRab18 transcripts were detected in the cDNA of adult worm, metacercaria, cercaria and egg of Clonorchis sinensis, and were highly expressed in the metacercaria. Immunohistochemical localization results revealed that CsRab18 was specifically deposited in the vitellarium and tegument of metacercaria. Furthermore, CsRab18WT and the active mutant CsRab18Q67L can stimulate basal lipogenesis in 3T3-L1 cells. We concluded from the present study that CsRab18 GTPase possibly contributes to the lipogenesis and nutrient absorption of Clonorchis sinensis and that the autophagy pathway could be an important site of action with respect to the developmental role of CsRab18 in Clonorchis sinensis.