In order to solve a series of vehicle vibration and noise problems caused by high-speed train in the process of lightweight and speeding, this paper focused on the influence of the parameters of the floor absorber on the sound reduction performance in the existing vehicle. Firstly, the interior noise characteristics and source are studied and identified to find out the significant frequency band, main noise source intensity and distribution characteristics. Secondly, the difference in vehicle noise characteristics are compared and analyzed before and after absorbers are installed inside the floor. Finally, based on the acoustic laboratory environmental test method, the various parameters of the floor absorber are researched and optimized. Studies show that the floor structure is the main sound transmission way and noise source distribution area. The installation of the floor absorber can effectively improve the sound insulation of the floor structure, thereby achieving the purpose of controlling the interior noise. Changing the stiffness, hardness, damping coefficient, load and quantity of the floor absorber has a certain influence on the sound insulation performance of the floor structure. The research results can provide a basis for the vibration and noise reduction design of high-speed trains.