This paper is concerned with a review of the size effect involved in the similar experimental models. The review covers in many fields, including size effect in microscopic system structure such as the study of the micro-beam mode, civil structure and mechanical structure such as the study of mechanical properties, the application of dynamic similarity model design in large structures. This is followed by the influencing factors of size effect and methods of predicting fatigue strength and fatigue life of large structures. Analysis of formulas for predicting the stress and strain, stress field near notched specimens used in large structures are established. Finally, the formulas for predicting the size factor and fatigue life of large structures about size effect are summarized and prospected.