To explore the detection effect of three combined BV tests for bacterial vaginosis (BV) of pregnant women during pregnancy, and to analyze the risk factors of vaginal infection of the women. Methods: 600 pregnant women were selected in study group from May 2019 to May 2020, which included 270 women during the first trimester of pregnancy, 180 women during the second trimester of pregnancy, and 150 women during the third trimester of pregnancy. In addition, 300 non-pregnant women were selected in control group during the same period. The situation of vaginal infection of the women in the two groups and the risk factors of BV of these women during pregnancy were analyzed. Results: The positive rate of candida (21.5%), vaginal cleanliness degree, and the positive rate of sialidase (21.0%) of the women in the study group were significant higher than those (5.0% and 19.0%) of the women in the control group (P＜0.05). Univariate analysis showed that there were significant differences in residence, previous childbirth history, occupation, current cervical erosion, underwear material, vulva cleaning situation, mental stress, spouse education level, spouse occupation between the women with BV during pregnancy and the women without BV during pregnancy (P＜0.05). Multivariate logistic regression analysis showed that residence, previous birth history, occupation, cervical erosion, underwear material, vulva cleaning, mental stress, spouse education, spouse occupation were the factors infecting BV of pregnant women during pregnancy (P＜0.05). Conclusion: The result of three combined detections for diagnosing BV of the pregnant women during pregnancy is reliable, and residence, previous birth history, occupation, current cervical erosion, underwear material, previous vulva cleaning, mental stress, spouse's education level, and spouse's occupation are the factors infecting BV of the women. The vaginal infection detection should be paid attention to for diagnosis and treatment of vaginal infection early and avoiding adverse pregnancy outcomes in clinical practice.