To investigate the short-term and long-term efficacy and safety of thalidomide in the treatment of intermediate and severe β-thalassemia. We analyzed patients with intermediate and severe β-thalassemia treated at our hospital from February 2019 to February 2024. Patients who received treatment for more than 3 months were included. The efficacy of thalidomide was assessed by comparing changes in hemoglobin (Hb), ferritin, bilirubin, and Hb electrophoresis before and after treatment. Adverse drug reactions during treatment were also recorded. A total of 42 β-thalassemia patients were included, with thalidomide dosages ranging from 75 to 150 mg/d. The response rates at 1, 3, and 6 months of treatment were 73.8% (31/42), 75.0% (24/32), and 94.7% (18/19), respectively. The increase in Hb levels was primarily attributed to fetal hemoglobin (HbF). After 1 month of treatment, the HbF percentage increased from a baseline of 34.04 ± 27.58% to 56.25 ± 28.40% (P < .001). At 3 and 6 months, HbF further increased to 67.21 ± 27.12% (P < .001) and 73.93 ± 22.96% (P < .001), respectively. The average duration of thalidomide treatment was 25.3 ± 9.2 months (range: 4-60 months), with 6 patients treated for over 60 months and 18 patients for over 48 months. Two homozygous patients who failed thalidomide treatment achieved Hb levels above 100 g/L and discontinued transfusion therapy after 3 months of hydroxyurea treatment. The most common adverse reaction was somnolence, which was mild and tolerable. Thalidomide demonstrates significant and sustained therapeutic effects in β-thalassemia patients. The adverse reactions are mild and tolerable, allowing patients to continue treatment.