Abstract: 　Objective　To explore the clinical manifestation and gene mutation of primary renal glucosuria (PRG). Methods　The clinical data and gene detection results of a child with PRG were analyzed. Results　A girl aged 2 years and 10 mouths had glucose ++++ by urine dipstick analysis and 22.4 g of the 24 h urine glucose. Her father was urine glucose positive. Genome DNA was extracted from peripheral blood of the girl and her parents, SLC5A2 gene were amplified by PCR for sequencing, including exons and splicing areas. The results showed a homozygous point mutation (c.127-16C>A) in girl, and both of her patents had the same heterozygous mutation. This mutation had been classified to pathogenic mutations by ClinVar data base. Conclusions　The diagnosis of PRG is confirmed in this child and SLC5A2 gene mutation is the cause.