Taking the legs of 1253 m jackup platform as object, a 3D model was established with ANSYS, stress response in the survival condition of the storm was analyzed, the leg risk node strength under this condition was checked; and a new detection method of dynamic strain simulated the wave impact in the splash zone was presented to estimate the dynamic properties and failure mechanism of engineering structure material under the impacts of wave and a device was designed to achieve the automation of dynamic strain detection, dynamic strain process on the leg material of high strength steel E690 were collected with this detection in the extreme impact loading, the dynamic mechanical properties of the material was analyzed, the material can meet the requirements of the use of limit condition.