Abstract: Objectives　To analyze SLC37A4 gene mutations in glycogen storage disease type Ib patients and to investigate the correlation between genotype and phenotype. Methods　The clinical data and SLC37A4 gene detection results of 3 cases of glycogen storage disease type Ib were analyzed retrospectively. Results　Two males and one female aged 6 years, 9 years, and 16 years respectively were presented with hepatomegaly, fasting hypoglycemia, slactic academia, hyperlipidemia, and granulocytopenia. The analysis of 6 alleles in SLC37A4 gene by  direct sequencing of peripheral blood DNA found 4 mutations, including 2 missense mutation (p. Leu23Arg and p.Pro191Leu), one shear mutation (c.870+5G>A), and one deletion mutation (c.1042_1043 del CT). The genotypes of these 3 cases were p.Pro191Leu, p.Pro191Leu；p. Leu23Arg, c.870+5G>A；p.Pro191Leu, p.Leu347ValfsX53 respectively. Conclusions　There were 4 mutations detected among these 3 cases of glycogen storage disease type Ib. All of those were known mutations. The most common mutation was p.Pro191Leu. It can not be excluded that P.Gly149Glu homozygous mutation is associated with repeated infections.