Research shows that when investigating the causal relation between phenomena, adopting a systematic view and assessing the feedbacks of involved variables could lead to much better results. In complex systems where humans act as significant components, the importance of systemic approach and focus on its dynamics become particularly more pronounced. Objective of this study was to use a system dynamics approach to study the safety culture and performance and its impacts on work-related accidents. This objective was pursued through introducing and determining the basic variables, plotting the causal and flow diagrams, and simulating the model by VENSIM software. In the next step, four different scenarios were defined to evaluate the model sensitivity and identify the leverage variables. The results of sensitivity analysis showed that production pressure is the key factor controlling the rate of work-related accidents in the studied organization, so adopting policies aimed at reducing the pressure of production can largely improve the level of accidents in this organization.