In the sarcoma S180 ascitic mice, the effects of moxa-cone moxibustion at Guanyuan (CV 4) on erythrocytic immunity and its regulative function were investigated. The results indicated that moxibustion at Guanyuan (CV 4) could significantly increase the decreased erythrocytic C3b receptor rosette forming rate (RBC-C3bRR), lower the raised erythrocytic immunocomplex rosette forming rate (RBC-ICR, P < 0.05 or P < 0.01), increase the decreased activity of erythrocytic immuno-accelerative factor, and reduce the increased activity of erythrocytic immunosuppressive factor (P < 0.05) in the tumor-bearing mice. This suggests that moxibustion at Guanyuan (CV 4) can strengthen erythrocytic immunity and promote its regulative function.