Abstract How trade liberalization affects a country's fertility has been verified by some studies, but little is known about how export trade liberalization impacts individual fertility intention. Using China Health and Nutrition Survey data from 1997 to 2011 and regression analysis, this study finds that a decline in the average external tariff significantly improves the fertility intentions of married women. This conclusion remains robust after overcoming endogeneity problems using an alternative external proxy variable, adopting different average tariff calculation methods, adding other control variables, and considering the son preference. The mechanism test shows that export trade liberalization can affect married women's fertility intentions by affecting family income; moreover, the income effect dominates the substitution and intra‐marital income gap effects. This study provides a new perspective for understanding changes in fertility intention in developing countries. This perspective can promote academic research progress in this field and be of great significance in formulating effective policies to improve fertility intention.