Abstract: Objective To understand the nutritional status and influencing factors of vitamin D in women before second pregnancy in Sichuan province,and to provide reference for formulating public health policies to improve the nutritional status of vitamin D and prevent its deficiency.Methods A total of 550 women with household registration in Sichuan Province before pregnancy were selected from the second child clinic and pre-pregnancy consultation in Sichuan Maternal and Child Health Hospital from August 2016 to May 2017.The serum 25-hydroxy-vitamin D concentration was determined by enzyme-linked immunosorbent assay(EUSA).Results The proportion of vitamin D deficiency and insufficiency in women before second pregnancy was relatively high. Age,ethnicity,family income and body weight per capita affected the level of vitamin D.Results The percentage of vitamin D deficiency was relatively high in Sichuan women before the second pregnancy,reaching 76.3% in this study. The vitamin D levels were relatively low in 20-25-year-old and ≥36-year-old women,ethnic minorities,families with an average annual income of more than 15,000,and overweight and obese women before pregnancy. It has an effect on the level of vitamin D in women before second pregnancy.Conclusion The vitamin D nutritional status of women with second child before pregnancy in Sichuan is poor,Health education on vitamin D deficiency should be strengthened and active intervention measures should be formulated. It is necessary to regularly evaluate the nutritional status of vitamin D and guide its effective and reasonable supplement,so as to provide a basis for follow-up nutrition intervention and related health policy formulation.