The Fourth Plenary Session of the 20th CPC Central Committee proposed advancing the citizenization of agricultural migrant population and implementing a system where basic public services are provided based on household registration at the place of permanent residence. Based on data on the fiscal costs and benefits of the citizenization of agricultural migrant population from 2019 to 2023， this study forecasts the fiscal costs and benefits of this process by the end of the 15th Five-Year Plan period in 2030 and assesses the impact of the citizenization of agricultural migrant population in China’s seven megacities on the local governments of their places of permanent residence.The assessment reveals that citizenization of agricultural migrant population generates net fiscal gains for their places of permanent residence， and the higher the proportion of agricultural migrant population in the resident population， the greater their contribution to local tax revenue. At the same time， agricultural migrant population plays a significant role in promoting the balance of revenues and expenditures in local social pension insurance funds. Furthermore， as the coverage of basic public services for agricultural migrant population expands， the fiscal costs of their citizenization for the places of permanent residence will rise rapidly； However， once these costs reach a certain level， they will gradually decline， and the net fiscal benefits derived by the places of permanent residence from citizenization will also gradually increase accordingly. Based on these findings， policy recommendations are proposed to provide decision-making references for local governments in advancing the citizenization of agricultural migrant population and implementing systems for providing basic public services to those who register permanent residency.