Abstract: ObjectiveTo understand the molecular epidemiological characteristics of norovirus infection in hospitalized children under 5 years old from 2012 to 2014 in Xinjiang.MethodsFecal specimens and epidemiological data were collected from 895 sick children aged ＜5 years hospitalized in Urumqi Hospital due to acute diarrhea from 2012 to 2014, and Real-time fluorescence quantitative-polymerase chain reaction (RT- PCR) was performed for norovirus detection. The positive specimens were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and sequenced.ResultsOf 895 specimens tested, 150 (16.8%) were detected as norovirus positive. The differences in positive rate among different years were significant (χ2＝21.080, P＜0.05) and the differences in positive rate among different age groups were significant too (χ2＝13.367, P＝0.020). Among the strains, 137 got the polymerase region sequencing. Out of 137 strains, 89 got the capsid protein region sequencing. The polymerase and capsid regions included 11 and 9 genotypes, respectively. GⅡ.4 DenHaag 2006b and GⅡ.Pe/GⅡ.4 Sydney 2012 accounted for 21.3% and 32.6%, respectively, and GⅡ.P12/GⅡ.3 accounted for 29.2%, according to the typing results of 89 strains in two regions. Among GⅡ.4 genotypes, the proportion of GⅡ.4 DenHaag 2006b was 90.0%, 0% and 0% from 2012 to 2014, respectively. GⅡ.Pe/GⅡ.4 Sydney 2012 accounted for 10.0%, 100% and 100%, respectively.ConclusionThe genetic diversity of norovirus in children with acute diarrhea in Urumqi of Xinjiang was found. GⅡ.Pe/GⅡ.4 Sydney appeared in Xinjiang in 2012, gradually replacing GⅡ.4 DenHaag 2006b as a new epidemic predominant strain.