The double-layer stiffened plate is widely used in modern transportation，The noise and vibration problems caused by such structures are still problems that people concerned. However，traditional control methods are difficult to meet the development needs of modern equipment due to their large additional weight，low reliability and narrow effective frequency band. Acoustic black hole（ABH），as a new type of wave manipulation technology，provides new ideas for vibration and noise reduction in the equipment. In this paper，ABH is applied to a double-layer stiffened plate to develop a structure with good mechanical properties，especially to reduce vibration and noise. A double layer stiffened plate-cavity system with ABHs is designed，and an experimental platform is built to test the effect. The results show that the broadband noise of the cavity can be reduced by 1.5~8 dB above cutoff frequency. A coupled numerical model is established based on finite elements，and the physical mechanism behind noise reduction is analyzed by quantifying the dynamic characteristics of the system from multiple angles. It can be seen that the ABH effect has dual characteristics in noise reduction，that is，increasing the damping of the system and reducing the coupling strength between inner-plate and cavity. Furthermore，the optimized design schemes are provided for the low frequency with poor noise reduction，widen the effective frequency and realize the control of the full-band. Finally，the universality of the noise reduction under complex loads is verified and analyzed.