We studied the expression features of Hepcidin (HEP), Erythropoietin (EPO), Albumin (ALB) and Prealbumin (PA), and the pathogenesis of anemia in tumor patients caused by radiotherapy. We tested the hemoglobin (HB) concentration in 446 cancer patients who received radiotherapy, and measured the serum HEP, EPO, ALB and PA n 92 cases to explore the pathogenesis of anemia caused by radiotherapy. The results were: (1) The HB level before and after radiotherapy in 446 patients were 119.85±19.87g/L and 116.32±24.25g/L (t=2.5211, P<0.05). The cases of anemia before and after radiotherapy were 146 cases and 175 cases (χ 2 =4.09, P<0.05). (2) The HB level before and after radiotherapy in 92 patients and in 20 cases of control group were respectively 127.33±17.12, 119.41±17.05 and 132.80±11.80g/L, the difference was statistically significant (F=11.70, P<0.01). The anemia cases were 14 and 27, respectively, which were also statistically significant (χ 2 =8.68, P<0.01). (3) The HEP level before and after radiotherapy in 92 patients and in 20 cases of control group were 3.38±2.48, 2.37±1.37 and 3.22±1.10mg/mL respectively, the difference was statistically significant (F=3.88, P<0.05). (4) EPO level before and after radiotherapy in 92 patients and in 20 controls were 5.05±3.50, 5.75±1.99 and 3.81±1.15mg/mL respectively, the difference was statistically significant (F=9.18, P<0.01). (5) The levels of ALB and PA before radiotherapy in 92 patients were higher than those after radiotherapy. ( 6) HEP was negatively correlated with HB before radiotherapy (r=-0.2938, t=2.9089, P<0.01), but HEP was not correlated with HB after radiotherapy (r=-0.0111, P>0.05). (7) There were positive correlation between ALB and HB before and after radiotherapy (all P<0.01). (8) There were positive correlation between PA and HB before and after radiotherapy (all P<0.01). Therefore, Radiotherapy could cause anemia and deteriorate nutritional status in cancer patients. Anemia negatively feedback inhibited the expression of HEP, while EPO was highly compensatory.