Abstract: Objective To explore the relationship between the levels of folic acid and compound vitamin B of perinatal women and neonatal birth weight.Methods Stratified multistage random sampling method was adopted in this study, and from January to December 2016, 8186 pregnant women were selected from urban areas. All the pregnant women were divided into three groups according to their nutritional status:pregnant women who took folic acid and vitamin B were group A (n=2182), those who only took folic acid during pregnancy were group B (n=4022), and those who did not take folic acid and vitamin B during pregnancy were group C (n=1982). Multilevel model was used to analyze the relationship between folic acid and vitamin B and neonatal birth weight.Results The indexes of age, years of education, family months income, the proportion of first birth primipara, the first production inspection gestational age ≤ 13 weeks, prenatal period test < 5 times, taking iron during pregnancy, anemia in pregnancy in the three groups was different, and the difference was statistically significant (P< 0. 05); The neonatal birth weight of group A was (3340. 21 ±160. 50) g, which was higher than that of group B and group C (P< 0. 05); The neonatal birth weight of group B was (3281. 16 ±270. 17) g, which was higher than that of group C (P< 0. 05); The results of Model O model showed that:compared with group B and group C, the neonatal birth weight of group A increased 50 g and 94 g, the difference was statistically significant (P< 0. 05); The Modell model showed that:compared with C group, the neonatal birth weight of group A increased an average of 75 g, the difference was statistically significant (P< 0. 05); compared with group B, neonatal birth weight in group A increased an average of 22 g, the difference was not statistically significant (P< 0. 05).Conclusion Taking folic acid during pregnancy can improve the birth weight of neonates, but vitamin B has no significant influence on the birth weight.