Based on the field work in a Pingdi Yao village in Fuchuan Yao Autonomous County, Guangxi, this paper analyses the intergenerational differences of fertility attitudes and their reasons in Pingdi Yao. In terms of the fertility concepts, the three generations of Pingdi Yao all show a persistent attitude towards reproduction, with divergence in fertility intentions. Compared with their grandparents and parents, social motivation of the young Pingdi Yao’s fertility has surpassed economic motivation to be the primary one, and the connotations of their emotional motivation have greatly been enriched as well. In terms of fertility willingness, the three generations of Pingdi Yao all look forward to having sons and daughters, showing a strong preference for having a boy. But with the passage of time, intergenerational differences manifest themselves in the weakened preference for boys, delayed intended age of giving birth to the first baby, decreasing intended fertility number, growing attention to the fertility quality, and diversified childbirth methods. The social-cultural roots of Pingdi Yao’s fertility attitude transformation lie in the increasing costs of nurture and marriage, the inheritance and transition of ethnic cultures, changes in social systems and gender conceptions, the influences of birth policies and maternal and children policies, and the emergence of a new young generation.