Abstract: Combing the subsystem modal coupling theory and the impedance-mobility approach,a general analytical models is developed for the analysis and active control of structural acoustic transmission through the double panel-cavity structure into the free field,in which control methods including incident panel piezoelectric (PZT) actuator,acoustic actuator in cavity,radiating panel PZT actuator are considered.The matrix formulae for calculating the modal response of the coupled structural acoustic system and optimal secondary source strengths are obtained.On the basis,active control of sound transmission through the double panel-cavity system is studied analytically and numerically in detail.Simulations and analyses are conducted to compare the control effects between different control strategies and examine the dominant control mechanisms involved in each control case,and the effect of system parameters on control effect is also examined.The results demonstrate that the incident panel actuator can obtain sound attenuation by modal suppression or rearrangement of three subsystems so complex control mechanisms are involved and it is effective for incident panel modes,cavity modes and radiating panel modes.Using the secondary acoustic source in the cavity is a better control strategy compared to the other control strategies due to the dominance of the acoustic mode (0,0,0) in the modal couplings and energy transmission in the low frequency range.