Objective To describe the distribution of birth weight of Beijing in 2013, and identify the influencing factors. Method Informations of 206 498 birth weight were collected form Beijing neonatal screening information management system, and comparative analysis on gender, gestational age, fetal number, residence, regional and other factors were progressed.Results The distribution of the birth weight was normal, the average birth weight was 3 350.12 g, the average birth weight of male was 3 400.28 g, the average birth weight of female was 3 295.64 g.The incidence of fetal macrosomia in male was more than 10%.With the increasing of the gestational age, the birth weight also increased, and reached peak at 42~43 weeks of pregnancy.The average birth weight among single birth newborns was larger than among multiple birth newborns.The average birth weight of newborn in rural area was higher than that in urban area.Conclusion In 2013, the average birth weight in Beijing is higher than the national data, newborn gender, gestational age, multiple and residence will produce more significant impacts.