Under the current development situation of electro-optical equipments, the new requirements for systems in complex electromagnetic environment are introduced, especially the new requirements for the development and verification of electro-optical systems from high intensity radiation field. The engineering design method of electromagnetic shielding is introduced. Incorporated with engineering practice, an engineering method of electromagnetic shielding effectiveness verification is presented. Two methods of shielding effectiveness verification are carried out based on the experiment testing and field testing methods. And linear extrapolation mode is introduced. The shielding design method has been verified in applications. Especially the shielding effectiveness verification method under high intensity radiation field has a strong guiding significance to the subsequent electro-optical equipment verification under complex environments.