In this paper, the radiation noise prediction, low-noise optimization design and experiment of gearbox are studied. Firstly, taking a single-stage herringbone gearbox as the research object, a finite element/boundary element model is established. Considering the vibration excitation of gear system, the radiation noise of single-stage gearbox is predicted based on modal acoustic transfer vector (MATV) method. Then, the maximum field point of radiated noise is determined, and the acoustic transfer vector (ATV) analysis and modal acoustic contribution(MAC) analysis are carried out to determine the region which contributes greatly to the radiated noise of the field point. Through the panel acoustic contribution(PAC) analysis, the optimization region is selected. Then, aiming at reducing the normal speed in the optimization region, topology optimization is carried out. According to the topology optimization results, noise reduction structures are added to the gearbox, and a low-noise optimization model of the gearbox is established. Finally, by measuring the radiated noise of the gearbox before and after optimization under a given working condition, the validity of the radiated noise prediction method and the low-noise optimization design method are verified by comparing the simulation and experimental data.