Introduction: The role of the hospital in maintenance and promotion of public health is more important in times of crisis because the hospitals also act as public shelters and a ray of hope for the affected population in the crisis. Therefore, preparation and continuous improvement of the hospital's safety against probable disasters is one of managerial key tasks. The aim of this research was to evaluate hospital safety index in Susa public hospital before and after interventions. Method: This is an action research study which was conducted from July 2015 to July 2016 in Susa public hospital, Khuzestan, Iran. The study was performed using Hospital Safety Index (HSI) checklist of the Iranian National Institute of Health Research (INIHR). The checklist has three main modules and 145 measures. The hospital was categorized based on A, B, and C level of safety. Result: The results showed that hospital safety index in the first year was at level C which after planned managerial interventions was promoted to the level B in the second year. Despite the partial improvement in the overall hospital safety index level in the second year, the safety level of three main modules including functional, structural, and non-structural safety was still at level C in both years. Despite the improvement of the overall hospital safety score in the second year, the safety score in three main modules remained at a level C. Conclusion: Therefore, the hospital's managers should address the hospital safety weaknesses using safety improvement techniques and quality improvement tools.