Abstarct: Structural health monitoring of critical structures have followed many scientist attraction in recent years. Optimal performance of a crude oil storage tank with increasing of the number of significant structural damage will reduce during in its lifetime. The importance of Diagnosis and management of failure is clear for professional. in this study the effect of corrosion fatigue Phenomenon over bottom plate of storage tanks due to moving up and down of their roof has investigated. Then with ANSYS software a crack in bottom plate has simulated and the amount of strains in different areas of around crack was resulted. The result of this simulation is benchmark for comparison with real data that taken from sensors. The result of this study show that the powerful structural health monitoring system for oil storage tanks , cause to avoid to impose high cost for unnecessary repairs and making facilities outside of services and knowing the level of healthing of tanks .according to these data , managers can make decision about operating , time and level of repairing of structures.