To investigate the effects of invitro fertilization/ intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET) of women with different body mass index (BMI) value who prepared for pregnancy on their pregnancy outcomes. Methods: A retrospective analysis was conducted on the data of the women who received IVF/ICSI-ET treatment from January 2020 to March 2023. These women were divided into three groups according to their BMI values, including group A (women with BMI<18.5kg/m2), group B (women with 18.5kg/m2≤ BMI <24.9kg/m2) and group C (women with BMI ≥24.9kg/m2). The clinical outcomes of the women after IVF/ICSI-ET were compared among the three groups. Logistic regression analysis was used to analyze the related factors affecting the clinical pregnancy rate and the live birth rate of the women in the three groups after IVF/ICSI-ET. Results: There were significant differences in the duration of infertility, the BMI value, the dosage of Gn used and the causes of infertility of the women among the three groups (P<0.05). There was no significant difference in the clinical pregnancy rates of the women among group A (36%, 31/86), group B (39.8%, 276/693) and group C (43.2%, 108/250). The abortion rate of the women in group A (16.1%, 5/31), in group B (10.1%, 28/276) and in group C (38.0%, 108/250) had no significantly different. The live birth rate of the women in group A (30.2%, 26/86), in group B (34.8%, 241/693) and in group C (26.4%, 66/250) had significantly different (P<0.05). Logistic multivariate regression analysis showed that the overweight and the high dosage of Gn used of the women with IVF/ICSI-ET were the factors affecting their clinical pregnancy, and the high dosage of Gn used of the women with IVF/ICSI-ET was the factors affecting their live birth (all P<0.05). Conclusion: Before undergoing IVF treatment, the achieving or approaching normal BMI of the women who prepared for pregnancy can improve their clinical outcomes after IVF/ICSI-ET.