Although the economy of a county that is linked to surrounding towns and rural areas constitutes a multiple basic economic unit within China's national economy, it usually exhibits independent characteristics and functions. Consequently, a county's economy plays a critical role in the overall economic development of a country's national economy. We created an evaluation index system based on entropy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to carry out a comprehensive evaluation of county economy across the entire Beijing-Tianjin-Hebei region. We found serious imbalances in the development of these counties, with county economies within Beijing and Tianjin being more advanced than those in Hebei Province. Furthermore, there were marked differences between county economies within prefecture-level cities of Hebei Province. The developmental level of counties in cities like Langfang, Tangshan and Chengde was relatively high. Conversely, the level of development of counties in Hengshui, Baoding, Xingtai and Handan was lower. Moreover, there were imbalances among cities in relation to county economic development, especially in Langfang, with smaller differences being found in Hengshui and Qinhuangdao. We analysed and identified the factors influencing differences between counties before providing recommendations.