With the increasing risk of China’s aging with lower fertility, how to boost the fertility rate back to an appropriate level has become a major issue of concern to the government and academia. The encouraging birth system represented by the three-child policy and the traditional birth culture with “more children and more happiness” as the core are highly anticipated to help China get rid of the “low fertility trap”. However, this study has different findings. First, the fertility rate of countries or regions in the Chinese cultural circle and overseas Chinese is far lower than that of other countries or ethnic groups. The traditional fertility culture has changed and declined in modern society, and its effect on the recovery of the low fertility rate is very limited. Instead, modern fertility culture, which tends to “have fewer (or no), better and later births”, has become popular, and has formed an endogenous low fertility mechanism. Second, European and East Asian countries are still trapped in the dilemma of low fertility rate after building an encouraging fertility system, and cannot effectively stimulate the low fertility rate to an appropriate level. The expected effect of China’s three-child fertility policy and its supporting measures are also not optimistic. There is a complex interrelationship among fertility culture, fertility system and fertility rate. Therefore, we need to re-examine the formation mechanism of fertility transformation in China from the structural and endogenous perspective of culture-system.