Objective To determine the potential categories of fertility motivation of pregnant women and examine the relationship between fertility motivation and maternal-fetal attachment, as well as the mediating role of subjective well-being, aiming to provide references for improving maternal-fetal attachment.Methods A cross-sectional survey was conducted in 413 pregnant women during the mid-to-late second trimester using the Maternal Antenatal Attachment Scale, the General Well-Being Schedule, and the Fertility Motivation Scale.The potential categories of fertility motivation were identified using latent class analysis, then the effects of different categories of fertility motivation on maternal-fetal attachment and the mediating effect of subjective well-being were analyzed bymediation analysis.Results Fertility motivation of pregnant women could be classified into four latent categories: autonomous (23.7%), controlled (23.7%), mixed (26.4%) and negative (26.2%).Mediation analysis revealed that, using the autonomous type as the reference, the relative direct effects of controlled type and negative type on maternal-fetal attachment were significant (β=-0.519,-0.612, both P＜0.05), and the relative indirect effect of subjective well-being was significant (β=-0.262,-0.221, both P＜0.05), indicating a partial mediating role of subjective well-being. In contrast, the relative direct effect of the mixed type was not significant (β=0.176,P=0.117).However, the relative effect of subjective well-being was significant (β=-0.118,P＜0.05),suggesting a complete mediating effect.Conclusion Pregnant women exhibit heterogeneous fertility motivation patterns, which have different effects on maternal-fetal attachment.The role of subjective well-being is also related to fertility motivation patterns.Precise interventions should be tailored for different groups based on these findings.