工程场址评价方法中传统的权重确定方法无法反映多元地学信息之间的复杂关系，影响评价结果的客观公正。为更好地满足大型工程设施选址的需要，将传统多因素相互作用关系矩阵法由常权改进为动态变权并引入工程场址评价，提出工程场址适宜度（ESSI）评价方法和定量评价指标，通过分析影响因素间作用关系及其在不同时空下对系统整体的影响，确定其在系统整体评价中根据实际情况动态变化的变权，根据权重计算工程场址适宜度。将该评价方法应用于中国散裂中子源工程选址工作，使用6个影响因素在5个比选场址中的变权及常权分别评价工程场址适宜度并对比分析，确定第3场址作为工程建设场址。实践证明基于多因素相互作用关系矩阵的ESSI评价方法与指标更具科学性、合理性和实用性，以期为类似工程选址提供参考。

The determination of the weights of the influencing factors in evaluating the suitability of engineering sites varies greatly among the conventional methods which are generally found unreliable when applied to some engineering sites with complex geology for their failure to reveal the complex relationships between the geological factors. To satisfy the need of selecting proper sites for large-scale key projects, we improve the constant weight to variety weight and introduce the matrix of multifactor interactions into the suitability evaluation of engineering sites, and propose the concept of engineering site suitability index (ESSI), a comprehensive index which is capable of considering the correlations between the influencing factors and the variation of their impact under various tamporospatial dimensions; and therefore put forward a multi-discipline system for evaluating the suitability of engineering sites. The system is used in the site selection for China Spallation Neutron Source(CSNC) Project, and found applicable and reliable by the follow-up engineering investigation. The ESSI system which is based on the matrix of multi-factor interactions is proved scientific, reasonable, and applicable by case studies; and it is expected to provide a reference for similar large-scale engineering