探究不确定环境下网络信息救济有效性的评估方法和影响因素，对于政府、相关机构和媒体提高信息救济质量具有重要的理论和实践意义。文章针对突发事件造成的不确定环境，基于社会支持理论将河北暴雨事件的网络信息分为社会支持需求和社会支持供给两个维度，基于信息救济的定义，将社会支持供给信息视作救济型信息，以不确定性缩减理论为基础，从减少不确定性策略的被动、主动、互动三个维度构建网络信息救济有效性评估体系，然后基于启发-系统模型，构建回归预测模型和SHAP模型，揭示影响网络信息救济有效性的关键因素。研究发现，不同生命周期和主题类型的信息救济有效性存在显著差异，爆发期和蔓延期信息救济有效性得分整体相对较高，潜伏期的态势消息、爆发期的救援信息、蔓延期的建议信息和恢复期的情绪信息在其所处阶段的救济有效性得分更高。发布者影响力和及时性对信息救济有效性有显著正向影响，信息情感性与信息救济有效性呈负相关。

Exploring the evaluation methods and influencing factors of the effectiveness of online information relief in uncertain environments has important theoretical and practical significance for governments, relevant institutions, and media to improve the quality of information relief. Aiming at the uncertain environment caused by public events, based on the social support theory, this study divides the online information of the rainstorm event in Hebei Province into two dimensions: social support demand and social support supply. Based on the definition of information relief, the social support supply information is regarded as relief information. Based on the uncertainty reduction theory, we construct an evaluation system for the effectiveness of online information relief from the passive, active and interactive dimensions of uncertainty reduction strategies. Then, based on the heuristic system model, a regression prediction model and a SHAP model are constructed to reveal the important factors affecting the effectiveness of online information relief. It is found that significant differences exist in the effectiveness of information relief across different life cycles and theme types. The overall scores for the effectiveness of information relief during the outbreak and spread periods were relatively high, while the situational information during the incubation period, rescue information during the outbreak period, recommendation information for the spread period, and emotional information during the recovery period score higher for the effectiveness of relief in their respective stages. The influence and timeliness of publishers have significant positive influence on the effectiveness of information relief, while the emotion of information is negatively correlated with the effectiveness of information relief.