The continuing decline in fertility and population ageing are major social issues facing the world today. On the one hand, population aging leads to a decrease in the total workforce and a decline in productivity, and with the increase in the proportion of elderly people, the pressure on social security, such as pension insurance and medical resources, will gradually increase. On the other hand, the decline in fertility rate means that the supply of new labor force will be insufficient. Therefore, a large number of countries have implemented various fertility policies to encourage the public to increase the fertility rate, so as to solve the negative impacts of low fertility rate and population aging on social development. This paper stands on the background of the three-child policy and investigates the fertility intention of Wenzhou residents and its influencing factors. Taking Ouhai District of Wenzhou as an example, this paper investigates the fertility situation of Ouhai residents, fertility intention, and the influencing factors of fertility intention from 1980 to 2023, and puts forward the suggestions to promote the fertility intention of residents in Ouhai District. It is expected that this paper can provide reference value for relevant government departments to effectively promote the three-child policy, so that more families are willing to continue to give birth, and effectively solve the problems of population aging and low fertility rate that China is currently facing.