Angiotensin II (Ang II) and calcitonin gene-related peptide (CGRP) play important roles in vascular injury and protection. In order to determine the role of CGRP receptor component protein (RCP) in signal transduction whereby CGRP and Ang II mediate the expression of vascular peroxidase-1 (VPO1) in vascular smooth muscle cell (VSMC), mouse derived A10 vascular smooth muscle cell line (A10VSMC) was cultured with CGRP or/and Ang II in vitro. RCP-specific small interference RNA (siRNA-RCP) was used to silence oligonucleotide sequence. Western blot and RT-PCR were used to determine the protein and mRNA expressions of RCP and VPO1, respectively. The results showed that the expressions of RCP and VPO1 were increased in the presence of CGRP or Ang II in the quiescent A10VSMC. But the protein expressions of RCP and VPO1 induced by Ang II were decreased by pretreatment of CGRP (P < 0.05). The expressions of VPO1 were decreased in all the groups treated with siRNA-RCP, compared with those of wide-type counterparts. Meanwhile, the expression of VPO1 was significantly induced by CGRP but not Ang II in the siRNA-RCP treated A10VSMCs. Ang II in combination with CGRP increased the protein expression of VPO1 in the siRNA-RCP-transfected cells, compared with Ang II alone, and this effect could be abolished by catalase. The results suggest that RCP may play an important role in the integration of signal transduction whereby CGRP and Ang II receptors jointly regulate VPO1 expression in VSMC.