Objective To investigate the effect of nerve growth factor(NGF)injection solution on immunosuppression in mice.Methods The immunosuppressed mice were induced by cyclophosphamide(Cy,80mg/kg,sc).The immunomodulatory effects of the drug were measured by cleaning carbon particle method,simple diffusion method,delayed type hypersensitivity(DTH),3H-TdR entering method and indirect immunofluorescence assay.Results The k value;a value,the level of serum IgG and ear swelling were remarkably decreased by NGF injection [0.01,0.1 mg/(kg? d)?10d,im].In addition,the number of L3T+4 Cells of peripheral blood and the ratio of L3T+4/Ly-2+ cell increase.Conclusion NGF has an enhanced effect on experimental immunosuppression in mice,which provides a theoretical basis for NGF treating tumor patients with nervous injure by chemotherapy or radiotherapy.