Velvet antler (VA) has been used for centuries as a traditional medicine to treat a wide range of health problems. VA was first recorded in the Chinese medical classics Shen Nong Ben Cao Jing 2000 years ago. VA has been extensively used to strengthen bones and muscles, promote blood flow and increase immune function. In the present study, we used VA (Cervus nippon Temminck) protein extract (VAPE) to induce cell proliferation and differentiation in human peripheral blood lymphocyte cell line 1301 cells. The results showed that 100 µg/mL of VAPE could significantly induce 1301-cell proliferation (151.3%), increase the population of S-phase cells and increase the expression of CDK4. In addition, VAPE could effectively increase the expression levels of PI3K and Akt and activate PI3K–Akt signal pathway. These findings have provided novel insights into the further understanding of the molecular and signalling pathway mechanisms of VAPE in promoting proliferation of human peripheral blood lymphocyte cells.