This study investigates the applicability of distorted models in predicting the frequencies and responses of coated thin plates. The significance of this study is that it provides the necessary scaling laws and structure size applicable intervals, which guide the design of distorted models. By comparing the effect of different coating thickness and different coating forms (single-sided coating and double-sided coatings), the direct use of a governing equation is employed to establish the scaling laws between the model and the prototype. Both complete and partial similarity is discussed. Then an aluminum-coated steel plate, which is commonly used, is analyzed as an example. Establishment of the structure size applicable interval is discussed, which should keep the same first-order natural characteristics (natural frequency and vibration mode). Applicable intervals of the distorted model under different orders are also obtained by using a numerical method. The applicability of the scaling laws and applicable intervals of coated thin plates are verified. The analytical results indicate that distorted models which satisfied the structure size applicable intervals can predict the characteristics of the prototype with good accuracy. This study provides a theoretical foundation for the design of scaled-down models of coated structures.