In the context of the increasing number of migrant workers and the growing trend of family-based migration, it becomes increasingly important to properly solve a series of problems brought about by their children's migration. Focusing on the wage reduction issue faced by female migrant workers due to their children's migration, this study, based on the motherhood wage penalty theory and, using the 2018 China Migrants Dynamic Survey data, divides the wage penalty of female migrant workers taking care of children into fertility and parenting penalties, and fi nds that fertility penalties reduce the wages of female migrant workers by 2.4%, while parenting penalties signifi cantly decrease their income by 11.0%. In single-child families, the parenting penalty caused by the migration of kindergarten-aged children is the most severe for new-generation female migrant workers with lower education levels. In two-child families, the parenting penalty caused by the migration of infants and toddlers is the most severe for them with higher education levels and is more than four times that caused by migration of peers in single-child families in the same age group. It is recommended in the study that supply of childcare services for two-child families, such as providing affordable day care, care, and household services within the payment ability of migrant workers' families, be strengthened to further unleash labor resources brought by migration and promote gender equality in the labor market.