针对液化天然气（liquefied natural gas, LNG）化工厂安全评价中存在模糊性、随机性等问题，提出了一种基于正态云模型的风险评估方法，该方法基于本质安全化选取评价指标，并通过专家评判量化事故可能性和严重度。通过结合层次分析法（analytic hierarchy process, AHP）和CRITIC（criteria importance through intercriteria correlation）赋权法确定各指标权重，利用正向云发生器柔化风险矩阵阈值，并通过逆向云发生器优化评价结果，从而得出云特征数字，并生成对应的二维云图。通过将实际云图与标准云图进行对比，确定各评价指标风险等级。以企业LNG化工厂为实例，结果表明：该模型有效融合了专家意见，保留了评估结果的随机性和模糊性，实现了风险评价结果可视化，为LNG化工厂安全管理提供了一种新的风险评估工具。

To address the fuzziness and randomness in safety evaluations of liquefied natural gas (LNG) chemical plants, a novel risk assessment method was proposed based on the normal cloud model. The proposed method was based on the selection of evaluation indicators from the perspective of intrinsic safety, which was used to evaluate the severity and likelihood of accidents through expert judgment. The weights of the indicators were determined by combining the analytic hierarchy process (AHP) and the criteria importance though intercrieria correlation (CRITIC). The risk matrix thresholds were softened using a forward cloud generator, and the evaluation results were optimized through a backward cloud generator to obtain cloud characteristic numbers and generate corresponding two-dimensional cloud maps. By comparing the actual cloud map with the standard cloud map, the risk levels of the evaluation indicators were determined. The results show that the model effectively integrates the expert opinions with aims of retaining the randomness and fuzziness, and providing the visualizes the risk assessment results. The novel method also provides a new risk assessment tool for the safety management of LNG chemical plants.