This study proposes a new approach to human reliability analysis (HRA) by introducing the occupational stress model in human resources management. Most existing HRA methods are restricted to a given set of risk factors in the task context, which are often called performance shaping factors (PSFs), and they are built on the causal relationship between PSFs and human performance, with little concern for the psychological factors that drive human behavior. We argue that a well‐developed occupational stress model that incorporates comprehensive working conditions and focuses on psychological factors offers us a new perspective to evaluate human reliability. The proposed approach, namely, the task demands‐resources (TD‐R) method, considers that the PSFs, in the task context, can be categorized into two different groups: task demands and task resources. These two PSF groups can both motivate and stress the operators during the task, thereby influencing their performances. Based on the theoretical framework of the TD‐R method, we also designed a probabilistic model linking motivational intensity to human error probability (HEP) under different stress levels. A human reliability experiment has been conducted to validate the effectiveness and flexibility of the TD‐R method. The experiment results showed that the TD‐R method could produce a meaningful explanation for the operators' performances and provide a quantification result for HEP.