Objective: To analyze the influencing factors of vitamin D in pregnant women in three,stage,s of pre-outbreak, post-outbreak and normalization of COVID-19 pandemic. Methods: The pregnant women who received prenatal examination in the First Hospital of Shanxi Medical University from May 2018 to May 2021 were selected as the research objects to detect vitamin D level, and analyze the effects of different pregnancy methods, delivery methods, age, gestational age, parity, number of parities and season on vitamin D level. Results: Totally 1 679 pregnant women were involved, the level of serum 25(OH) D in pregnant women was 18.70 (12.60, 27.20)ng/mL. The rate of vitamin D deficiency was 24.41%, 51.01% and 34.23% of three stages of pre-outbreak, post-outbreak and normalization of COVID-19 pandemic, the difference was statistically significant (P<0. 001). Orderly multiple Logistic regression analysis showed that early pregnancy [OR=0.359,95% CI (0.2,57, 0.502)], maternal age <35 years old [OR=0.766, 95% CI (0.598, 0.980)], winter [OR=0.388, 95% CI (0.290, 0.520)], spring [OR=0.350, 95% CI (0.258, 0.475)] and summer [OR=1.533, 95% CI (1.166, 2.014)] had an effect on vitamin D deficiency in pregnant women. Conclusion: The rate of vitamin D deficiency in pregnant women is high. Pregnancy, season and age are independent influencing factors of vitamin D deficiency in pregnant women. After the normalization of COVID-19 pandemic, pregnant women should supplement vitamins scientifically and individually, strengthen the education of nutrition during pregnancy, and regularly monitor the level of vitamin D.