Recently, increasing evidences show that procyanidin (PC) modulate immune responses in human. To evaluate adjuvant effects of PC on vaccine immune modulation and anti-tumor activity, we formulated PC with B16F10 tumor antigen as tumor vaccine to immune C57BL/6 mice and used intramuscular injection before challenge with tumor B16F10 cells. Our results revealed that PC enhanced T cell-mediated immune responses both in vitro and in vivo. Moreover, the B16F10 tumor vaccine induced some degree of anti-tumor effects as evaluated by the inhibition of tumor growth and the prolongation of survival. The tumor-bearing mice showed a high level of specific cytotoxic activity and had activated CD8 T cells that secreted perforin, IFN-γ and TNF-α in response to the stimulation with antigen in vitro. Taken together, current study presents evidence that PC may be used as a promising vaccine adjuvant.