Abstract: The evaluation of the ecological suitability of agricultural land can clarify the constraints of agricultural land production and ecological function, which is conducive to targeted zoning and classified policies, so as to improve the sustainable use level of regional agricultural land. Taking Huanghua City in the Bohai Rim region as an example, this paper constructs an evaluation index system of ecological suitability of “soil resources-water resources” composite farmland, and uses the method of combining single index evaluation and hierarchical evaluation to identify the limiting factors and degree of ecological suitability of agricultural land. Based on the results of the comprehensive evaluation, according to the principle of consistency of improvement technical measures, the agricultural land consolidation zones were divided, and the improvement measures were put forward accordingly. The results showed that the ecological suitability of chemical fertilizer application rate, organic matter content and soil salt content of agricultural land in the study area was poor, and the unsuitable grades reached 87.47%, 99.62% and 25.34%, respectively. The groundwater mineralization of agricultural land in the whole area was too high, the groundwater depth in the eastern part was shallow, and the irrigation guarantee rate of 69.54% of agricultural land was insufficient. In addition, other indicators were in an appropriate state. The main limiting factors of agricultural land in the study area were as follows: chemical fertilizer application rate, organic matter content, soil salinity content, groundwater salinity, groundwater burial depth and irrigation guarantee rate. The combination of limiting factors was divided into two categories such as the composite type of “dominant limiting factor（severe） + secondary limiting factor（mild）” and the single type with only mild limiting factors, accounting for 91.9% and 8.1%, respectively. Two types of remediation areas were divided into “soil fertilization area” and “saline soil improvement area”, and the targeted remediation and improvement measures were put forward. The results of this study can provide a practical reference for the improvement and utilization of agricultural land in coastal areas with complex ecosystem conditions.