China has entered an era of low fertility, showing low fertility intention and declining number of births. Using the 2012-2021 Chinese General Social Survey (CGSS) data, this study constructs an index system to measure subjective well-being based on the “sense of gain, happiness and security” (i.e., three senses of people's livelihood) proposed in the 19th National Congress report of the CPC. It measures people's fertility intention from two aspects: the intention to have children and the ideal number of children. This study explores the influence of subjective well-being on fertility intention and reveals a significant positive impact. Specifically, the sense of happiness mainly affects the ideal number of children, while the sense of security mainly affects the intention to have children. The sense of gain significantly influences both aspects and exhibits the largest effect. Moreover, with the development of China's economy and the gradual liberalization of the fertility policy, the positive influence of the subjective well-being on the intention to have children is gradually weakening, while its influence on the ideal number of children is increasing.