To investigate the effect of transfer factor (TF) on the immune efficacy of porcine circovirus type 2 (PCV2) subunit vaccine, spleen from healthy porcine was grinded and the homogenate was frozen thawed six times. TF was obtained after the homogenate was centrifuged and ultrafiltered. After physical and chemical inspection, TF was added to PCV2 subunit vaccine (Cap vaccine), named TF-Cap vaccine. TF-Cap vaccine and Cap vaccine were used to immunize mice with physiological saline as control. The mice were separated into two groups: one-time vaccination and two-time vaccination. Blood was collected at 10-d interval through caudal vein after the first vaccination and PCV2 antibody was tested using indirect enzyme-linked immuno-sorbent assay. The result showed that the concentration of the ultrafiltered TF is 1.83 mg/mL. Detection of PCV2 specific antibody showed that there are significant differences (P<0.01) between vaccine group and control group while there is no significant differences (P>0.05) among vaccine groups. However, PCV2 antibody titer in mice immunized TF-Cap vaccine only once was comparable to mice immunized Cap-vaccine twice, indicating PCV2 subunit vaccine with TF can enhance the antibody production.