Building a balanced and accessible basic public service system is an important measure to promote the high-quality development of counties and townships. Based on the perspective of county governance, this paper logically analyzes the balanced development of basic public services from internal equality and external balance, employs the entropy weight TOPSIS method to measure and evaluate the level of basic public services in counties, uses the Dagum Gini coefficient and its decomposition to measure and analyze the equalization of basic public services in counties, and investigates the synchronization of basic public services with economic and social development using the coupling and coordination degree model. The results of the study are as follows. First, the level of basic public service has shown a marked improvement in China’s counties. The growth rate of basic public services is faster in the south than in the north, with districts outperforming counties. Non-poor counties dominate, yet poor counties are growing at a faster pace. Second, there is a trend towards equalization of basic public services in the counties. The speed and level of equalization in the South are better than in the North. The North-South gap is narrowing. The degree of imbalance in the districts is higher, but the urban-rural gap is gradually narrowing. The imbalance in the non-poor counties is more severe. Third, basic public services have been developing in a more balanced manner in relation to both economic growth and fiscal capacity. The situation is better in the South, which is now better than in the North. Districts do significantly better than counties. Non-poor counties do significantly better than poor counties. The results of this study offer significant insights into achieving balanced development of basic public services at the county level through a dual strategy of internal parity and external equalization. Additionally, they provide guidance for promoting common prosperity.