Objective:To analyze the thalassemia screening and genotyping in Southwest Guizhou Autonomous Prefecture (referred it as Qianxinan Prefecture), this essay provides the theoretical reference for clinical diagnosis of thalassemia and suspicious cases.Methods:The pregnant women, spouses and neonates who were screened for thalassemia gene in Qian Xi Nan People's Hospital from January 2016 to December 2020 were selected as the research subjects, and peripheral blood or umbilical cord blood samples were collected to extract DNA. The gap-polymerase chain reaction (Gap-PCR) and next-generation sequencing (NGS) technology were used to screen thalassemia, and ArcMap 10.8 software was adopted to map the local spatial distribution of thalassemia based on the screening data.Results:A total of 67 185 cases of people from various regions in Qianxinan Prefecture were screened, and 8 202 cases of thalassemia gene carriers were detected, with a total detection rate of 12.21%. Among them, 5 660 cases of α-thalassemia, with a detection rate of 8.42%; 2 132 cases of β-thalassemia, with a detection rate of 3.17%; 410 cases of αβ complex thalassemia, with a detection rate of 0.61%. In the detection of thalassemia genes, 27 genotypes of α-thalassemia were detected, mainly αα/-α 3.7, accounting for 41.13% (2 328/5 660); 33 genotypes of β-thalassemia were detected, mainly β CD17(A>T)/β A, accounting for 44.09% (940/2 132); 55 genotypes of αβ complex thalassemia were detected, and αα/-α 3.7 complexed β CD17(A>T)/β A dominated, accounting for 21.22% (87/410). There were high incidence areas in the spatial distribution of thalassemia, which were Wangmo County and Ceheng County, and the detection rate was 26.76% (1 438/5 374), 24.39% (1 314/5 387), respectively. Conclusions:The detection rate of thalassemia gene in Qianxinan Prefecture is relatively high, mainly αα/-α 3.7 genotype of α-thalassemia. Wangmo County and Ceheng County are high-incidence areas of thalassemia, and screening efforts should be continued.