In order to clarify the status of agricultural soil fertility in Julu County of Hebei Province and guide the sustainable development of regional agriculture, 1628 soil samples were systematically collected in this study. The key fertility indexes such as soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), available potassium (AK), and pH value were analyzed. The membership function was used to calculate the comprehensive fertility index (SCFI) of soil, and the soil quality was comprehensively evaluated. The results showed that the soils in Julu County were generally weakly alkaline, with an average value of pH 8.24. Specifically, SOM content was relatively low (average: 9.97 g/kg), TN was relatively abundant (average: 1.36 g/kg), AP was insufficient (average: 11.62 mg/kg), AK was enriched (average: 203.83 mg/kg), available iron (Avail-Fe) was at an appropriate level (average: 7.88 mg/kg), available manganese (Avail-Mn) was abundant (average: 23.15 mg/kg), while available copper (Avail-Cu) (average: 16.50 mg/kg) and available zinc (Avail-Zn) (average: 50.72 mg/kg) exceeded the standard limits. Among these indicators, the coefficients of variation (CV) of TN, AP, SOM, Avail-Mn, and Avail-Cu were relatively high, being 0.36, 0.33, 0.35, 0.45, and 0.41, respectively. The SCFI of soils in various towns and townships of Julu County ranged from 0.58 to 0.62, and their spatial distribution presented a pattern of being higher in the west and lower in the east, and decreasing from the central area to the north and south. Soil fertility was mainly affected by SOM, AP, and TN. Appropriately increasing the application of organic materials and applying phosphate fertilizer in a certain proportion could effectively improve the comprehensive soil fertility of this region, thereby further promoting the sustainable development of local agriculture.