Objectives　To explore the clinical and gene mutation characteristics of Gitelman syndrome in children. Method　The clinical data of 3 children with Gitelman syndrome were retrospectively analyzed. Results　All three cases were male and their age were 3, 8 and 10 years . The clinical manifestations were hypokalemia, hypomagnesemia, alkalosis, hyperreninemia, and hyperaldosteronemia. Gene detection revealed a complex heterozygous mutation in the SLC12A3 gene. A total of 5 mutation sites were found in the SLC12A3 gene, c.179C>T (Thr60Met), c.248 G>A (Arg83Gln), c.2129 C>A (Ser710X), c.2660+1G>A, c.1456G>A (Asp486Asn). After the diagnosis was confirmed, they were treated with potassium supplement, magnesium supplement, and spironolactone and the conditions were improved in all cases. Conclusions　In children with hypokalemia, be aware of Gitelman syndrome, and gene detection is helpful for the diagnosis.