Abstract: OBJECTIVE To investigate the diagnostic value with blood test for diagnosing thalassemia and iron deficiency anemia in patients combined with infections, and to provide basis for effective clinical diagnosis of anemia. METHODS A total of 80 cases of patients with anemia and concurrent infection in the hospital for blood test from Jan. 2014 to Dec. 2015 were selected, and divided into experimental group one with 20 cases of iron deficiency anemia and experimental group two with 60 cases of thalassemia, at the same time, 40 cases of healthy people who received blood routine test in the hospital were selected as control group. Related clinical data of patients in the three groups were compared. The results were statistically analyzed by software SPSS17.0. RESULTS The red blood cell counts, hemoglobin concentrations,and average hemoglobin concentrations in the experimental group one were (3.12±0.58) 10¹²/L, (69.1±4.2) g/L and (256.3±1.2) g/L, while they were (4.98±1.23) 10¹² / L, (92.3±3.7) g/L and (342.6±2.7) g/L in the thalassemia group, and the difference was statistically significant (P<0.05). The red blood cell distribution in the iron deficiency anemia group was higher than that of the thalassemia group (P<0.05). CONCLUSION Blood routine test has an extremely important clinical significance on diagnosing and identifying thalassemia and iron deficiency anemia combined with infection, with fast operation, simple, inexpensive characteristics, and it is worth promoting.