Abstract: Objective:To investigate the effect of compound heterozygous non-deletional hereditary persistence of fetal hemoglobin(nd-HPFH)on hemoglobin H disease(Hb H disease).Methods:A total of 148 patients diagnosed as Hb H disease by thalassemia screening in the First Affiliated Hospital of Guangxi Medical University from January 2022 to December 2022 were collected.Blood routine tests were performed on the subjects, and hemoglobin (Hb) analysis was performed by high performance liquid chromatography.DNA sequencing was used for detecting the mutation of γ-globin gene.Mutations of α-and β-thalassemia genes were detected by fluorescent PCR melting curve analysis and Gap-PCR methods.Results:Among 148 patients with Hb H disease, 44 cases with compound nd-HPFH were detected, the gene detection rate was 29.7%, including 27 cases of^Gγ-158C> T mutant heterozygotes, 13 cases of^Aγ-225 to-222 deletion heterozygotes, 2 cases of^Gγ-158C> T mutant homozygotes, 1 case of^Gγ-158C> T mutant heterozygote combined with^Aγ-225 to-222 deletion homozygote, 1 case of^Gγ-158C> T mutant heterozygote combined with^Aγ-225 to-222 deletion heterozygote.The results of Hb analysis showed that 1 case had elevated fetal hemoglobin (Hb F)(5.3%).Blood routine results were as follows: 19 cases with mild anemia, 24 cases with moderate anemia and 1 case with severe anemia.Thalassemia genotyping results were as follows: 20 cases with--^SEA/α^CSα, 13 cases with--^SEA/-α^3.7, 9 cases with--^SEA/-α^4.2, 1 case with--^SEA/α^QSα and 1 case with--^THAI/-α^3.7.Conclusion:The nd-HPFH mutation has a high detection rate in patients with Hb H disease, and there are differences in clinical anemia in patients with nd-HPFH combined with Hb H disease.Most of these patients have normal Hb F levels and are easy to be missed clinically.