Global fertility rate has been decreasing for decades but the world is not well-prepared for this challenge. Are the raising perceived cost of childrearing discouraging the fertility? How do people’s fertility plans response to potential fertility subsidies? In two separate large field survey experiments in China, we answer both questions and propose potential intervention on boosting fertility in developing countries. The first experiment documents people’s perceived cost and benefit of childrearing, fertility plan and optimal number of children. In study 1, we randomize the information provisions of the actual cost of child-rearing among the average population in the province and the benefit of additional child. In study 1, we can answer whether treated people can update their perceived cost of childrearing. And whether information change their fertility planning. In study 2, we randomize the amount of fertility subsidies, under the incentive that their decision will affect the design of the subsidies. We can find how people’s fertility planning responses to the change of fertility subsidies.