暴雨引发的山洪和城市积涝是危害严重的自然灾害之一，传统暴雨洪涝风险评估中对地形因子统一赋值，无法区分地形对山洪与城市积涝的不同成灾机制。通过分别对山洪与城市积涝的地形因子赋值，构建了融合致灾因子和分灾种孕灾环境的精细化致灾风险模型，实现了对2种灾害孕灾环境的机理化分区和综合风险融合。以秦皇岛为实证区域，验证了该模型的有效性。结果表明：①该模型有效区分了秦皇岛地区山洪与城市积涝的孕灾环境，中南部平坦地区因城镇耕地集中，城市积涝孕灾环境指数高，北部及东北部山区则因地形起伏大、河网密集，山洪孕灾环境指数高；②暴雨综合高风险区主要位于秦皇岛市中部地区，是暴雨强度指数与孕灾环境高值叠加区；③历史暴雨过程灾情与模型输出的综合风险指数显著相关，表明该模型对实际灾害态势具有较好的指示意义。

[Objective] Addressing the increasing demands for disaster prevention and mitigation，it is essential not only to enhance the accuracy of rainstorm forecasting but also to assess in advance the potential disaster-causing risks posed by rainstorms. In contrast to evaluation models that rely on uniform topographic factors，this study aims to reflect the distinct disaster mechanisms of mountain torrents and urban waterlogging，thereby accurately revealing the comprehensive risk patterns of regional flood disasters caused by rainstorms. [Methods] By assigning specific topographic factors to mountain torrents and urban waterlogging respectively，this study develops a refined disaster-causing risk model that integrates hazard-inducing factors and disaster-specific hazard-inducing environments. The model enables mechanism-based zonation of the hazard-inducing environments for both disaster types and the integration of comprehensive risks. Taking Qinhuangdao as the empirical area，the validity of the proposed model is verified. [Results] （1） Fine-scale modeling of the hazard-formative environment effectively distinguishes the disaster-prone contexts for flash floods and urban waterlogging. The flat central-southern plains，characterized by concentrated urban and agricultural land，show a high hazard-formative environmental index for urban waterlogging，while the mountainous northern and northeastern areas，with significant topographic relief and dense river networks，exhibit a high index for flash floods. （2） The comprehensive high-risk zones for torrential rain disasters in Qinhuangdao are mainly located in the central part of the city，representing areas where high hazard intensity overlaps with highly sensitive disaster-prone environments. （3） The comprehensive risk index of historical rainstorm events shows correlation coefficients R of 0.721，0.698，and 0.724 with direct economic loss （GDP），affected population，and affected crop area，respectively，all passing the significance test at α=0.05. The correlation coefficient R between the comprehensive disaster index and the comprehensive risk index across counties （districts） reaches 0.912，passing the significance test at α=0.01，indicating that the model has good indicative significance for actual disaster situations. [Conclusions] The refined comprehensive risk model developed in this study，which integrates hazard-inducing factors and disaster-specific hazard-forming environments，effectively captures the differential mechanisms of mountain torrents and urban waterlogging. This model not only offers a unified framework for accurately delineating the regional pattern of comprehensive rainstorm and flood risk，providing a paradigm for flood risk assessment in analogous regions，but also can be applied to dynamic risk assessment for single hazard-inducing processes.