Abstract: Salidroside and salidroside-loaded nanoliposomes were administered to mice, and then the mice were exposed to X-ray. Indices including periphery blood cell, DNA content in the medulla, MDA content, SOD and GSH-Px activity in the livers and spleens, lymphocyte transformation of periphery blood were measured.The blood system in the SLN-treated groups was protected better than that of SN-treated groups. Cell level of periphery blood was significantly resumed. DNA content in the medulla increased, and apoptosis of lymphocyte in periphery blood was inhibited to a great extent. Furthermore, spleen index and thymus index were enhanced.Results of MDA content, SOD and GSH-Px activity in the livers and spleens showed that peroxidation level of membrane lipids decreased and antioxidative capacity increased in SLN-treated groups. Therefore, SLN had a significant protective effect against sub-acute radiation damage.