Objective: To investigate the efficacy and incidence of adverse reactions of therapeutic erythrocytapheresis in high altitude polycythemia (HAPC) population. Methods: A retrospective study was conducted on 243 HAPC patients who were either native residents or long-term workers in Xizang and underwent therapeutic erythrocytapheresis in the Chengdu Office Hospital of the People's Government of Xizang Autonomous Region from 2021 to 2023. A comparative study was carried out on the changes in blood routine, vital signs, skin color, serum iron metabolism data, and the incidence of adverse reactions before and after the procedure. Results: After erythrocytapheresis, significant decreases were observed in red blood cell (RBC) count (7.06±0.89×10 vs 6.08±0.93×10 /L, P<0.001], hemoglobin (HGB, 211.59±17.99 vs 182.76±19.83 g/L, P<0.001), hematocrit (Hct) [(65.30±6.45)% vs (55.56±8.12)%, P<0.001], serum iron (14.46±4.38 vs 11.77±3.78 μmol/L, P=0.003), total iron-binding capacity (126.62±4.47 vs 123.73±3.77 μmol/L, P=0.002), transferrin (1.88±0.41 vs 1.77±0.12 g/L, P=0.023), transferrin saturation [(11.32±3.11)% vs (9.43±2.78)%, P=0.004], serum ferritin (832.4±295.6 vs 665.3±249.2 ng/mL, P<0.001), systolic blood pressure (123.86±14.43 vs 118.51±13.68 mmHg, P<0.001) and diastolic blood pressure (81.68±9.54 vs 74.28±7.61 mmHg, P<0.001). In contrast, platelet count (Plt, 137.21±46.21 ×10 vs 147.94±50.66 ×10 /L, P<0.001) and oxygen saturation [(93.97±3.29)% vs (95.84±2.27)%, P<0.001] increased. No significant differences were found in white blood cell (WBC) count [5.35 (4.59, 6.44)×10 /L vs 5.43 (4.54, 6.53) ×10 /L, P=0.690], unsaturated iron-binding capacity (112.15±0.50 vs 111.96±0.25 μmol/L, P=0.074) and pulse rate (73.42±11.28 vs 73.19±7.18 beats/min, P=0.750). Furthermore, skin color of the face (conjunctiva, lips) and palms mitigated after therapeutic erythrocytapheresis, changing from purplish-red to red. The total incidence of adverse reactions during erythrocytapheresis was 13.98% (34/243), including citrate toxicity 12.75% (31/243), puncture site hematoma 0.82% (2/243) and blood volume imbalance 0.41% (1/243). Conclusion: Therapeutic erythrocytapheresis could rapidly decrease HCT, Hb, serum iron, transferrin and transferrin saturation levels in HAPC patients, with a low incidence of adverse reactions. Therefore, therapeutic erythrocytapheresis has broad clinical application prospects in Xizang Autonomous Region.