Objective To investigate the incidence and genetic testing results of congenital adrenal hyper⁃ plasia（CAH）in Guangxi，China. Methods A total of 391，714 newborns born in 168 midwifery hospitals in the region from 2015 to 2021 were selected as subjects. The time⁃resolved fluorescence method was used to detect 17⁃hydroxyprogesterone（17⁃OHP）. The suspected positive children were recalled for retesting，which was done together with relevant clinical auxiliary tests. Sanger sequencing combined with multiplex ligation ⁃dependent probe amplification（MLPA）technology was used to detect the CYP21A2 genes in the children and determine the genotypes. Results Among the 391，714 newborns，1，769 were initially positive for CAH，and 21 were diagnosed between 2 and 27 days old，with an incidence of 1/18653. At the same time，gene mutations were found in all diagnosed children，and CYP21A2 gene variation was diversified，among which c. 293⁃13A/C > G was the frequent mutation， with an incidence of 33%. Conclusions By 21⁃hydroxylase genic testing，the point mutation and large fragment deletion of CYP21A2 gene can be detected. Combined with the elevation of 17⁃OHP and clinical manifestations，CAH in children can be effective diagnosed，thereby preventing the occurrence of life⁃threatening adrenal cortical crisis.