Background: The inclusion of assisted reproductive technology (ART) in medical insurance coverage represents not only a breakthrough in the healthcare sector, but also a critical measure to implement the national population development strategy. By January 1, 2025, 31 provincial-level administrative regions and the Xinjiang Production and Construction Corps have incorporated ART into their medical insurance reimbursement schemes. However, existing studies have primarily focused on the impacts of this policy in the medical field, while neglecting its supporting role in the national population development strategy. Methods: Taking the policy practice of incorporating ART into medical insurance reimbursement as the entry point, this paper uses self-collected survey data and applies the Logit model to investigate the policy effect, group heterogeneity, and regional heterogeneity of this policy on the fertility intentions of the reproductive-age population. Results: First, the inclusion of ART in medical insurance reimbursement improves the fertility intentions of the reproductive-age population as a whole, with an overall increase of 2.9%, and this result passes a series of robustness tests. Second, the policy has a stronger positive effect on the fertility intentions of relatively older reproductive-age individuals, rural residents, and relatively low-income groups, who are the most direct beneficiaries of the policy. Third, the policy effect on fertility intentions is stronger among groups in regions that provide prenatal and postnatal care guidance, infertility prevention and treatment, reproductive health services, as well as childcare and family service centers, which indicates that attention should be paid to the coordination of fertility support policies. Fourth, in provincial-level administrative regions where ART was first included in the medical insurance reimbursement scope, projects with high coverage and multiple payment mechanisms have a stronger promoting effect on the fertility intentions of the reproductive-age group. However, the higher medical care level and the more frequent usage restrictions have weakened the intensity of the increase in fertility intentions. Conclusions: On the premise of ensuring the stable operation of the medical insurance fund, provincial-level administrative regions should prioritize expanding the scope of ART items eligible for medical insurance reimbursement, set reasonable limits on the level of medical security and the number of reimbursements, and actively provide supporting fertility-related services, so as to better promote the construction of a fertility-friendly society.