〔Abstract〕 Objective To explore the value of blood test in the diagnosis of anemia. Methods A total of 173 patients with anemia who were treated in Sanming First Hospital from June 2020 to June 2022 were randomly selected, including 84 patients with iron deficiency anemia and 89 patients with thalassemia. According to the severity of anemia, they were divided into 116 patients with mild anemia, 37 patients with moderate anemia and 20 patients with severe anemia. Another 71 healthy subjects who received physical examination at the same time were randomly selected for disease diagnosis and differentiation using blood test technology. Comparison between iron deficiency anemia, the thalassemia patients and healthy subjects and patients with different degree of anemia of the average amount of mean corpsular hemoglobin (MCH), mean hemoglobin concentration (MCHC), red blood cell volume distribution width (RDW), mean corpuscular volume (MCV), concentration of hemoglobin (Hb), red blood cell count (RBC) and serum ferritin (SF), and the efficacy of blood test in diagnosing thalassemia and iron deficiency anaemia was calculated. Results The levels of MCH, MCHC, MCV, Hb, RBC and SF in patients with thalassemia and iron deficiency anemia were lower than those in healthy subjects, and the level of RDW was higher than that in healthy subjects. The levels of MCH, MCHC, Hb, RBC and SF in patients with thalassemia were higher than those in patients with iron deficiency anemia, while the levels of RDW and MCV were lower than those in patients with iron deficiency anemia, and the differences were statistically significant (P < 0.05). The sensitivity, specificity and accuracy of blood test for thalassemia and iron deficiency anemia were 96.53 %, 90.28 % and 95.08 %, respectively. The levels of MCH, MCHC, MCV, Hb, RBC and SF in patients with moderate and severe anemia were lower than those in patients with mild anemia, and the level of RDW was higher than that in patients with mild anemia. The levels of MCH, MCHC, MCV, Hb, RBC and SF in patients with severe anemia were lower than those in patients with moderate anemia, and the level of RDW was higher than that in patients with moderate anemia, and the differences were statistically significant (P < 0.05). Conclusion Blood test technology is helpful to differentiate thalassemia from iron deficiency anemia, and can also provide guidance for clinical assessment of anemia severity.