The disease severity and patient complexity are extremely high in the intensive care unit (ICU). The objective structured simulation training can effectively improve clinical management, caring ability, decision-making skills and teamwork communication, and hence. Purpose: This study aims to utilize the high-fidelity patient simulator in the ICU when clinical staff handles the emergent situation of arrhythmia, and to also evaluate the ability of handling emergent situations and the effectiveness of teamwork. Methods: The study was conducted in a mixed ICU of a medical center in the northern Taiwan, with a total of 13 training sessions and 87 trainees. The one-group pre-test and post-test design were used and participants were assessed by the Learning Milestone Self-Assessment Form and Simulation evaluation Form before, after, and 3 months after the training course. Results: The results indicated that no matter nurses, resident doctors or intern doctors, the scores of self-assessment conducted before and after training were statistically significant (p < .001). There was also a significant difference between the evaluation result before training and three months after training. The simulation training evaluation before and after training were statistically significant (p < .001). After three months of training, the scores of nurses reached statistically significant differences with the pre-training curriculum(p < .001). Conclusions: The high-fidelity simulation in objective structured clinical training can successfully lead to increased handling ability of the clinical staff , better team competitiveness, and enhanced efficacy and quality of medical care.