OBJECTIVE To analyze the difference of genotypes and hearing phenotypes in infants with biallelic allele variant in GJB2,and to provide reference for clinical practice. METHODS One hundred and forty-two subjects with biallelic allele variant in GJB2 were recruited in Beijing Tongren Hospital from August 2012 to March 2024. All subjects received universal newborn hearing screening(UNHS),neonatal deafness genetic screening and audiological tests. The subjects were divided into three groups according to the genotypes:T/T groups(truncated/truncated mutations,59 cases),T/NT group(truncated/non-truncated mutations,50 cases) and NT/NT group(non-truncated/non-truncated mutations,33 cases). Three groups of genotypes,newborn hearing screening results,age at first diagnosis and hearing diagnosis results were analyzed. RESULTS The homozygous mutation of c.235delC/c.235delC was the dominant in T/T group(57.63％),the compound heterozygous mutation of c.235delC/c.109G>A was the dominant in T/NT group(74.00％),and the homozygous mutation of c.109G>A/c.109G>A was the dominant in NT/NT group(96.97％). The overall refer rate of UNHS was 80.28％,and the refer rate of T/T group was 89.83％,which was significantly higher than that of T/NT group 70.00％(P=0.009). The age of first diagnosis of 142 cases was (3.70±1.56) months,there was no significant difference between the three groups(P>0.05). In 142 cases,104 cases with hearing loss accounted for 73.24％,38 cases with normal hearing accounted for 26.76％. The proportion of confirmed hearing loss in T/T group was 100.00％,which was significantly higher than that in T/NT group 52.00％(P<0.001) and NT/NT group 57.58％(P<0.001). In side of hearing loss,of the 104 patients with hearing loss,86 cases(82.69％) had bilateral hearing loss and 18 cases(17.31％) had unilateral hearing loss. The proportion of bilateral hearing loss in T/T group was 100.00％,which was significantly higher than that in T/NT group 57.69％(P<0.001) and NT/NT group 63.16％(P<0.001). Among 190 ears of 104 patients with hearing loss,the degree of hearing loss was predominantly mild to moderate(63.16％),followed by profound(24.74％) and severe(12.10％). Among them,the T/T group was mainly marked by severe to profound hearing loss(58.47％),while both the T/NT group and the NT/NT group were mainly characterized by mild hearing loss(58.54％ and 74.19％),and the differences among the three groups were statistically significant(P<0.001). CONCLUSION In the T/T group,all patients were diagnosed as bilateral hearing loss at first diagnosis,and was mainly severe and profound hearing loss. The bilateral and unilateral hearing loss were 52.00％ and 57.58％ in the T/NT group and NT/NT group at first diagnosis respectively,and was mainly mild hearing loss.