Abstract: Objective To analyze the birth weight of infants with different gestational weeks, fetus number and gender, to explore the incidence and the change of low birth weight infants(LBWI) from 2015 to 2019 in Yunfu, China, to explore its related risk factors, and finally to provide evidence and data t for government departments to formulate relevant policies to reduce the occurrence of LBWI. Methods An investigation was carried out based on the birth weight of 180,378 singleton live births delivered in 66 midwifery institutions in Yunfu during 2015-2019, univariate analysis of variance and multivariate logistic regression were used to analyze the influencing factors. Result The mean birth weight was(3,108. 33 ± 417. 61) g, and it showed an increasing trend with the increase of gestational weeks(P< 0. 001). The incidence of premature, low birth weight, macrosomia, small for gestational age and large than gestational agewas 4.97%, 5.18%, 2.13%, 14.76%, and 3.52%, respectively. The risk factors of low birth weight(LBW) were maternal age <20 years old(OR, 95% CI:0. 35,1. 23-1. 56), preterm birth(OR, 95% CI: 3. 44,29. 69-32. 92), Puerpera(OR,95% CI: 0. 36,1. 37-1. 51) and birth defects(OR, 95% CI:0. 95(2. 13-3. 15). The risk factors for macrosomia were maternal age ≥35 years old(OR, 95% CI:0. 59, 1. 66-1. 96), postterm birth(OR, 95% CI: 1. 24,2. 81-4. 21), male infant(OR, 95% CI: 0. 61,1. 73-1. 98)and non-guangdong household registration(OR, 95% CI: 0. 498,1. 46-1. 85). Conclusion The average birth weight, premature birth rate, macrosomia and low birth weight infant were lower than the national average level. Low birth weight infant is affected by maternal age, premature delivery, parturient and birth defects. Macrosomia was affected by sex, maternal age, psotterm birth and maternal household registration.