Abstract: A prediction method is proposed for the transient vibration analysis of line-coupled plates at high frequencies.Based on transient statistical energy analysis, a time-domain scaling law is derived from the dynamic similitude of transient energy equilibrium equations for subsystems. It features a damping loss factor scaled inversely proportional to the scaling of the time variable. On this basis, specific scaling forms for line-coupled plates are derived. Two completely different realizations of the specific scaling forms are presented. One only scales material parameters and the other dimension parameters. Numerical validations on two kinds of line-coupled plates demonstrate that this approach can efficiently predict the transient vibration response.